| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| Issue summary: An OpenSSL TLS 1.3 server may fail to negotiate the expected
preferred key exchange group when its key exchange group configuration includes
the default by using the 'DEFAULT' keyword.
Impact summary: A less preferred key exchange may be used even when a more
preferred group is supported by both client and server, if the group
was not included among the client's initial predicated keyshares.
This will sometimes be the case with the new hybrid post-quantum groups,
if the client chooses to defer their use until specifically requested by
the server.
If an OpenSSL TLS 1.3 server's configuration uses the 'DEFAULT' keyword to
interpolate the built-in default group list into its own configuration, perhaps
adding or removing specific elements, then an implementation defect causes the
'DEFAULT' list to lose its 'tuple' structure, and all server-supported groups
were treated as a single sufficiently secure 'tuple', with the server not
sending a Hello Retry Request (HRR) even when a group in a more preferred tuple
was mutually supported.
As a result, the client and server might fail to negotiate a mutually supported
post-quantum key agreement group, such as 'X25519MLKEM768', if the client's
configuration results in only 'classical' groups (such as 'X25519' being the
only ones in the client's initial keyshare prediction).
OpenSSL 3.5 and later support a new syntax for selecting the most preferred TLS
1.3 key agreement group on TLS servers. The old syntax had a single 'flat'
list of groups, and treated all the supported groups as sufficiently secure.
If any of the keyshares predicted by the client were supported by the server
the most preferred among these was selected, even if other groups supported by
the client, but not included in the list of predicted keyshares would have been
more preferred, if included.
The new syntax partitions the groups into distinct 'tuples' of roughly
equivalent security. Within each tuple the most preferred group included among
the client's predicted keyshares is chosen, but if the client supports a group
from a more preferred tuple, but did not predict any corresponding keyshares,
the server will ask the client to retry the ClientHello (by issuing a Hello
Retry Request or HRR) with the most preferred mutually supported group.
The above works as expected when the server's configuration uses the built-in
default group list, or explicitly defines its own list by directly defining the
various desired groups and group 'tuples'.
No OpenSSL FIPS modules are affected by this issue, the code in question lies
outside the FIPS boundary.
OpenSSL 3.6 and 3.5 are vulnerable to this issue.
OpenSSL 3.6 users should upgrade to OpenSSL 3.6.2 once it is released.
OpenSSL 3.5 users should upgrade to OpenSSL 3.5.6 once it is released.
OpenSSL 3.4, 3.3, 3.0, 1.0.2 and 1.1.1 are not affected by this issue. |
| Issue summary: Applications using RSASVE key encapsulation to establish
a secret encryption key can send contents of an uninitialized memory buffer to
a malicious peer.
Impact summary: The uninitialized buffer might contain sensitive data from the
previous execution of the application process which leads to sensitive data
leakage to an attacker.
RSA_public_encrypt() returns the number of bytes written on success and -1
on error. The affected code tests only whether the return value is non-zero.
As a result, if RSA encryption fails, encapsulation can still return success to
the caller, set the output lengths, and leave the caller to use the contents of
the ciphertext buffer as if a valid KEM ciphertext had been produced.
If applications use EVP_PKEY_encapsulate() with RSA/RSASVE on an
attacker-supplied invalid RSA public key without first validating that key,
then this may cause stale or uninitialized contents of the caller-provided
ciphertext buffer to be disclosed to the attacker in place of the KEM
ciphertext.
As a workaround calling EVP_PKEY_public_check() or
EVP_PKEY_public_check_quick() before EVP_PKEY_encapsulate() will mitigate
the issue.
The FIPS modules in 3.6, 3.5, 3.4, 3.3, 3.1 and 3.0 are affected by this issue. |
| Issue summary: Converting an excessively large OCTET STRING value to
a hexadecimal string leads to a heap buffer overflow on 32 bit platforms.
Impact summary: A heap buffer overflow may lead to a crash or possibly
an attacker controlled code execution or other undefined behavior.
If an attacker can supply a crafted X.509 certificate with an excessively
large OCTET STRING value in extensions such as the Subject Key Identifier
(SKID) or Authority Key Identifier (AKID) which are being converted to hex,
the size of the buffer needed for the result is calculated as multiplication
of the input length by 3. On 32 bit platforms, this multiplication may overflow
resulting in the allocation of a smaller buffer and a heap buffer overflow.
Applications and services that print or log contents of untrusted X.509
certificates are vulnerable to this issue. As the certificates would have
to have sizes of over 1 Gigabyte, printing or logging such certificates
is a fairly unlikely operation and only 32 bit platforms are affected,
this issue was assigned Low severity.
The FIPS modules in 3.6, 3.5, 3.4, 3.3 and 3.0 are not affected by this
issue, as the affected code is outside the OpenSSL FIPS module boundary. |
| Issue summary: During processing of a crafted CMS EnvelopedData message
with KeyTransportRecipientInfo a NULL pointer dereference can happen.
Impact summary: Applications that process attacker-controlled CMS data may
crash before authentication or cryptographic operations occur resulting in
Denial of Service.
When a CMS EnvelopedData message that uses KeyTransportRecipientInfo with
RSA-OAEP encryption is processed, the optional parameters field of
RSA-OAEP SourceFunc algorithm identifier is examined without checking
for its presence. This results in a NULL pointer dereference if the field
is missing.
Applications and services that call CMS_decrypt() on untrusted input
(e.g., S/MIME processing or CMS-based protocols) are vulnerable.
The FIPS modules in 3.6, 3.5, 3.4, 3.3 and 3.0 are not affected by this
issue, as the affected code is outside the OpenSSL FIPS module boundary. |
| Issue summary: During processing of a crafted CMS EnvelopedData message
with KeyAgreeRecipientInfo a NULL pointer dereference can happen.
Impact summary: Applications that process attacker-controlled CMS data may
crash before authentication or cryptographic operations occur resulting in
Denial of Service.
When a CMS EnvelopedData message that uses KeyAgreeRecipientInfo is
processed, the optional parameters field of KeyEncryptionAlgorithmIdentifier
is examined without checking for its presence. This results in a NULL
pointer dereference if the field is missing.
Applications and services that call CMS_decrypt() on untrusted input
(e.g., S/MIME processing or CMS-based protocols) are vulnerable.
The FIPS modules in 3.6, 3.5, 3.4, 3.3 and 3.0 are not affected by this
issue, as the affected code is outside the OpenSSL FIPS module boundary. |
| Issue summary: When a delta CRL that contains a Delta CRL Indicator extension
is processed a NULL pointer dereference might happen if the required CRL
Number extension is missing.
Impact summary: A NULL pointer dereference can trigger a crash which
leads to a Denial of Service for an application.
When CRL processing and delta CRL processing is enabled during X.509
certificate verification, the delta CRL processing does not check
whether the CRL Number extension is NULL before dereferencing it.
When a malformed delta CRL file is being processed, this parameter
can be NULL, causing a NULL pointer dereference.
Exploiting this issue requires the X509_V_FLAG_USE_DELTAS flag to be enabled in
the verification context, the certificate being verified to contain a
freshestCRL extension or the base CRL to have the EXFLAG_FRESHEST flag set, and
an attacker to provide a malformed CRL to an application that processes it.
The vulnerability is limited to Denial of Service and cannot be escalated to
achieve code execution or memory disclosure. For that reason the issue was
assessed as Low severity according to our Security Policy.
The FIPS modules in 3.6, 3.5, 3.4, 3.3 and 3.0 are not affected by this issue,
as the affected code is outside the OpenSSL FIPS module boundary. |
| Issue summary: An uncommon configuration of clients performing DANE TLSA-based
server authentication, when paired with uncommon server DANE TLSA records, may
result in a use-after-free and/or double-free on the client side.
Impact summary: A use after free can have a range of potential consequences
such as the corruption of valid data, crashes or execution of arbitrary code.
However, the issue only affects clients that make use of TLSA records with both
the PKIX-TA(0/PKIX-EE(1) certificate usages and the DANE-TA(2) certificate
usage.
By far the most common deployment of DANE is in SMTP MTAs for which RFC7672
recommends that clients treat as 'unusable' any TLSA records that have the PKIX
certificate usages. These SMTP (or other similar) clients are not vulnerable
to this issue. Conversely, any clients that support only the PKIX usages, and
ignore the DANE-TA(2) usage are also not vulnerable.
The client would also need to be communicating with a server that publishes a
TLSA RRset with both types of TLSA records.
No FIPS modules are affected by this issue, the problem code is outside the
FIPS module boundary. |
| Issue summary: A type confusion vulnerability exists in the signature
verification of signed PKCS#7 data where an ASN1_TYPE union member is
accessed without first validating the type, causing an invalid or NULL
pointer dereference when processing malformed PKCS#7 data.
Impact summary: An application performing signature verification of PKCS#7
data or calling directly the PKCS7_digest_from_attributes() function can be
caused to dereference an invalid or NULL pointer when reading, resulting in
a Denial of Service.
The function PKCS7_digest_from_attributes() accesses the message digest attribute
value without validating its type. When the type is not V_ASN1_OCTET_STRING,
this results in accessing invalid memory through the ASN1_TYPE union, causing
a crash.
Exploiting this vulnerability requires an attacker to provide a malformed
signed PKCS#7 to an application that verifies it. The impact of the
exploit is just a Denial of Service, the PKCS7 API is legacy and applications
should be using the CMS API instead. For these reasons the issue was
assessed as Low severity.
The FIPS modules in 3.5, 3.4, 3.3 and 3.0 are not affected by this issue,
as the PKCS#7 parsing implementation is outside the OpenSSL FIPS module
boundary.
OpenSSL 3.6, 3.5, 3.4, 3.3, 3.0, 1.1.1 and 1.0.2 are vulnerable to this issue. |
| Issue summary: An invalid or NULL pointer dereference can happen in
an application processing a malformed PKCS#12 file.
Impact summary: An application processing a malformed PKCS#12 file can be
caused to dereference an invalid or NULL pointer on memory read, resulting
in a Denial of Service.
A type confusion vulnerability exists in PKCS#12 parsing code where
an ASN1_TYPE union member is accessed without first validating the type,
causing an invalid pointer read.
The location is constrained to a 1-byte address space, meaning any
attempted pointer manipulation can only target addresses between 0x00 and 0xFF.
This range corresponds to the zero page, which is unmapped on most modern
operating systems and will reliably result in a crash, leading only to a
Denial of Service. Exploiting this issue also requires a user or application
to process a maliciously crafted PKCS#12 file. It is uncommon to accept
untrusted PKCS#12 files in applications as they are usually used to store
private keys which are trusted by definition. For these reasons, the issue
was assessed as Low severity.
The FIPS modules in 3.5, 3.4, 3.3 and 3.0 are not affected by this issue,
as the PKCS12 implementation is outside the OpenSSL FIPS module boundary.
OpenSSL 3.6, 3.5, 3.4, 3.3, 3.0 and 1.1.1 are vulnerable to this issue.
OpenSSL 1.0.2 is not affected by this issue. |
| Issue summary: An application using the OpenSSL HTTP client API functions may
trigger an out-of-bounds read if the 'no_proxy' environment variable is set and
the host portion of the authority component of the HTTP URL is an IPv6 address.
Impact summary: An out-of-bounds read can trigger a crash which leads to
Denial of Service for an application.
The OpenSSL HTTP client API functions can be used directly by applications
but they are also used by the OCSP client functions and CMP (Certificate
Management Protocol) client implementation in OpenSSL. However the URLs used
by these implementations are unlikely to be controlled by an attacker.
In this vulnerable code the out of bounds read can only trigger a crash.
Furthermore the vulnerability requires an attacker-controlled URL to be
passed from an application to the OpenSSL function and the user has to have
a 'no_proxy' environment variable set. For the aforementioned reasons the
issue was assessed as Low severity.
The vulnerable code was introduced in the following patch releases:
3.0.16, 3.1.8, 3.2.4, 3.3.3, 3.4.0 and 3.5.0.
The FIPS modules in 3.5, 3.4, 3.3, 3.2, 3.1 and 3.0 are not affected by this
issue, as the HTTP client implementation is outside the OpenSSL FIPS module
boundary. |
| Issue summary: A timing side-channel which could potentially allow remote
recovery of the private key exists in the SM2 algorithm implementation on 64 bit
ARM platforms.
Impact summary: A timing side-channel in SM2 signature computations on 64 bit
ARM platforms could allow recovering the private key by an attacker..
While remote key recovery over a network was not attempted by the reporter,
timing measurements revealed a timing signal which may allow such an attack.
OpenSSL does not directly support certificates with SM2 keys in TLS, and so
this CVE is not relevant in most TLS contexts. However, given that it is
possible to add support for such certificates via a custom provider, coupled
with the fact that in such a custom provider context the private key may be
recoverable via remote timing measurements, we consider this to be a Moderate
severity issue.
The FIPS modules in 3.5, 3.4, 3.3, 3.2, 3.1 and 3.0 are not affected by this
issue, as SM2 is not an approved algorithm. |
| Issue summary: An application trying to decrypt CMS messages encrypted using
password based encryption can trigger an out-of-bounds read and write.
Impact summary: This out-of-bounds read may trigger a crash which leads to
Denial of Service for an application. The out-of-bounds write can cause
a memory corruption which can have various consequences including
a Denial of Service or Execution of attacker-supplied code.
Although the consequences of a successful exploit of this vulnerability
could be severe, the probability that the attacker would be able to
perform it is low. Besides, password based (PWRI) encryption support in CMS
messages is very rarely used. For that reason the issue was assessed as
Moderate severity according to our Security Policy.
The FIPS modules in 3.5, 3.4, 3.3, 3.2, 3.1 and 3.0 are not affected by this
issue, as the CMS implementation is outside the OpenSSL FIPS module
boundary. |
| Issue summary: Processing a malformed PKCS#12 file can trigger a NULL pointer
dereference in the PKCS12_item_decrypt_d2i_ex() function.
Impact summary: A NULL pointer dereference can trigger a crash which leads to
Denial of Service for an application processing PKCS#12 files.
The PKCS12_item_decrypt_d2i_ex() function does not check whether the oct
parameter is NULL before dereferencing it. When called from
PKCS12_unpack_p7encdata() with a malformed PKCS#12 file, this parameter can
be NULL, causing a crash. The vulnerability is limited to Denial of Service
and cannot be escalated to achieve code execution or memory disclosure.
Exploiting this issue requires an attacker to provide a malformed PKCS#12 file
to an application that processes it. For that reason the issue was assessed as
Low severity according to our Security Policy.
The FIPS modules in 3.6, 3.5, 3.4, 3.3 and 3.0 are not affected by this issue,
as the PKCS#12 implementation is outside the OpenSSL FIPS module boundary.
OpenSSL 3.6, 3.5, 3.4, 3.3, 3.0, 1.1.1 and 1.0.2 are vulnerable to this issue. |
| Issue summary: A type confusion vulnerability exists in the TimeStamp Response
verification code where an ASN1_TYPE union member is accessed without first
validating the type, causing an invalid or NULL pointer dereference when
processing a malformed TimeStamp Response file.
Impact summary: An application calling TS_RESP_verify_response() with a
malformed TimeStamp Response can be caused to dereference an invalid or
NULL pointer when reading, resulting in a Denial of Service.
The functions ossl_ess_get_signing_cert() and ossl_ess_get_signing_cert_v2()
access the signing cert attribute value without validating its type.
When the type is not V_ASN1_SEQUENCE, this results in accessing invalid memory
through the ASN1_TYPE union, causing a crash.
Exploiting this vulnerability requires an attacker to provide a malformed
TimeStamp Response to an application that verifies timestamp responses. The
TimeStamp protocol (RFC 3161) is not widely used and the impact of the
exploit is just a Denial of Service. For these reasons the issue was
assessed as Low severity.
The FIPS modules in 3.5, 3.4, 3.3 and 3.0 are not affected by this issue,
as the TimeStamp Response implementation is outside the OpenSSL FIPS module
boundary.
OpenSSL 3.6, 3.5, 3.4, 3.3, 3.0 and 1.1.1 are vulnerable to this issue.
OpenSSL 1.0.2 is not affected by this issue. |
| Issue summary: Calling PKCS12_get_friendlyname() function on a maliciously
crafted PKCS#12 file with a BMPString (UTF-16BE) friendly name containing
non-ASCII BMP code point can trigger a one byte write before the allocated
buffer.
Impact summary: The out-of-bounds write can cause a memory corruption
which can have various consequences including a Denial of Service.
The OPENSSL_uni2utf8() function performs a two-pass conversion of a PKCS#12
BMPString (UTF-16BE) to UTF-8. In the second pass, when emitting UTF-8 bytes,
the helper function bmp_to_utf8() incorrectly forwards the remaining UTF-16
source byte count as the destination buffer capacity to UTF8_putc(). For BMP
code points above U+07FF, UTF-8 requires three bytes, but the forwarded
capacity can be just two bytes. UTF8_putc() then returns -1, and this negative
value is added to the output length without validation, causing the
length to become negative. The subsequent trailing NUL byte is then written
at a negative offset, causing write outside of heap allocated buffer.
The vulnerability is reachable via the public PKCS12_get_friendlyname() API
when parsing attacker-controlled PKCS#12 files. While PKCS12_parse() uses a
different code path that avoids this issue, PKCS12_get_friendlyname() directly
invokes the vulnerable function. Exploitation requires an attacker to provide
a malicious PKCS#12 file to be parsed by the application and the attacker
can just trigger a one zero byte write before the allocated buffer.
For that reason the issue was assessed as Low severity according to our
Security Policy.
The FIPS modules in 3.6, 3.5, 3.4, 3.3 and 3.0 are not affected by this issue,
as the PKCS#12 implementation is outside the OpenSSL FIPS module boundary.
OpenSSL 3.6, 3.5, 3.4, 3.3, 3.0 and 1.1.1 are vulnerable to this issue.
OpenSSL 1.0.2 is not affected by this issue. |
| Issue summary: When using the low-level OCB API directly with AES-NI or<br>other hardware-accelerated code paths, inputs whose length is not a multiple<br>of 16 bytes can leave the final partial block unencrypted and unauthenticated.<br><br>Impact summary: The trailing 1-15 bytes of a message may be exposed in<br>cleartext on encryption and are not covered by the authentication tag,<br>allowing an attacker to read or tamper with those bytes without detection.<br><br>The low-level OCB encrypt and decrypt routines in the hardware-accelerated<br>stream path process full 16-byte blocks but do not advance the input/output<br>pointers. The subsequent tail-handling code then operates on the original<br>base pointers, effectively reprocessing the beginning of the buffer while<br>leaving the actual trailing bytes unprocessed. The authentication checksum<br>also excludes the true tail bytes.<br><br>However, typical OpenSSL consumers using EVP are not affected because the<br>higher-level EVP and provider OCB implementations split inputs so that full<br>blocks and trailing partial blocks are processed in separate calls, avoiding<br>the problematic code path. Additionally, TLS does not use OCB ciphersuites.<br>The vulnerability only affects applications that call the low-level<br>CRYPTO_ocb128_encrypt() or CRYPTO_ocb128_decrypt() functions directly with<br>non-block-aligned lengths in a single call on hardware-accelerated builds.<br>For these reasons the issue was assessed as Low severity.<br><br>The FIPS modules in 3.6, 3.5, 3.4, 3.3, 3.2, 3.1 and 3.0 are not affected<br>by this issue, as OCB mode is not a FIPS-approved algorithm.<br><br>OpenSSL 3.6, 3.5, 3.4, 3.3, 3.0 and 1.1.1 are vulnerable to this issue.<br><br>OpenSSL 1.0.2 is not affected by this issue. |
| Issue summary: Writing large, newline-free data into a BIO chain using the
line-buffering filter where the next BIO performs short writes can trigger
a heap-based out-of-bounds write.
Impact summary: This out-of-bounds write can cause memory corruption which
typically results in a crash, leading to Denial of Service for an application.
The line-buffering BIO filter (BIO_f_linebuffer) is not used by default in
TLS/SSL data paths. In OpenSSL command-line applications, it is typically
only pushed onto stdout/stderr on VMS systems. Third-party applications that
explicitly use this filter with a BIO chain that can short-write and that
write large, newline-free data influenced by an attacker would be affected.
However, the circumstances where this could happen are unlikely to be under
attacker control, and BIO_f_linebuffer is unlikely to be handling non-curated
data controlled by an attacker. For that reason the issue was assessed as
Low severity.
The FIPS modules in 3.6, 3.5, 3.4, 3.3 and 3.0 are not affected by this issue,
as the BIO implementation is outside the OpenSSL FIPS module boundary.
OpenSSL 3.6, 3.5, 3.4, 3.3, 3.0, 1.1.1 and 1.0.2 are vulnerable to this issue. |
| Issue summary: Use of the low-level GF(2^m) elliptic curve APIs with untrusted
explicit values for the field polynomial can lead to out-of-bounds memory reads
or writes.
Impact summary: Out of bound memory writes can lead to an application crash or
even a possibility of a remote code execution, however, in all the protocols
involving Elliptic Curve Cryptography that we're aware of, either only "named
curves" are supported, or, if explicit curve parameters are supported, they
specify an X9.62 encoding of binary (GF(2^m)) curves that can't represent
problematic input values. Thus the likelihood of existence of a vulnerable
application is low.
In particular, the X9.62 encoding is used for ECC keys in X.509 certificates,
so problematic inputs cannot occur in the context of processing X.509
certificates. Any problematic use-cases would have to be using an "exotic"
curve encoding.
The affected APIs include: EC_GROUP_new_curve_GF2m(), EC_GROUP_new_from_params(),
and various supporting BN_GF2m_*() functions.
Applications working with "exotic" explicit binary (GF(2^m)) curve parameters,
that make it possible to represent invalid field polynomials with a zero
constant term, via the above or similar APIs, may terminate abruptly as a
result of reading or writing outside of array bounds. Remote code execution
cannot easily be ruled out.
The FIPS modules in 3.3, 3.2, 3.1 and 3.0 are not affected by this issue. |
| Issue summary: Applications performing certificate name checks (e.g., TLS
clients checking server certificates) may attempt to read an invalid memory
address resulting in abnormal termination of the application process.
Impact summary: Abnormal termination of an application can a cause a denial of
service.
Applications performing certificate name checks (e.g., TLS clients checking
server certificates) may attempt to read an invalid memory address when
comparing the expected name with an `otherName` subject alternative name of an
X.509 certificate. This may result in an exception that terminates the
application program.
Note that basic certificate chain validation (signatures, dates, ...) is not
affected, the denial of service can occur only when the application also
specifies an expected DNS name, Email address or IP address.
TLS servers rarely solicit client certificates, and even when they do, they
generally don't perform a name check against a reference identifier (expected
identity), but rather extract the presented identity after checking the
certificate chain. So TLS servers are generally not affected and the severity
of the issue is Moderate.
The FIPS modules in 3.3, 3.2, 3.1 and 3.0 are not affected by this issue. |
| Issue summary: Calling the OpenSSL API function SSL_select_next_proto with an
empty supported client protocols buffer may cause a crash or memory contents to
be sent to the peer.
Impact summary: A buffer overread can have a range of potential consequences
such as unexpected application beahviour or a crash. In particular this issue
could result in up to 255 bytes of arbitrary private data from memory being sent
to the peer leading to a loss of confidentiality. However, only applications
that directly call the SSL_select_next_proto function with a 0 length list of
supported client protocols are affected by this issue. This would normally never
be a valid scenario and is typically not under attacker control but may occur by
accident in the case of a configuration or programming error in the calling
application.
The OpenSSL API function SSL_select_next_proto is typically used by TLS
applications that support ALPN (Application Layer Protocol Negotiation) or NPN
(Next Protocol Negotiation). NPN is older, was never standardised and
is deprecated in favour of ALPN. We believe that ALPN is significantly more
widely deployed than NPN. The SSL_select_next_proto function accepts a list of
protocols from the server and a list of protocols from the client and returns
the first protocol that appears in the server list that also appears in the
client list. In the case of no overlap between the two lists it returns the
first item in the client list. In either case it will signal whether an overlap
between the two lists was found. In the case where SSL_select_next_proto is
called with a zero length client list it fails to notice this condition and
returns the memory immediately following the client list pointer (and reports
that there was no overlap in the lists).
This function is typically called from a server side application callback for
ALPN or a client side application callback for NPN. In the case of ALPN the list
of protocols supplied by the client is guaranteed by libssl to never be zero in
length. The list of server protocols comes from the application and should never
normally be expected to be of zero length. In this case if the
SSL_select_next_proto function has been called as expected (with the list
supplied by the client passed in the client/client_len parameters), then the
application will not be vulnerable to this issue. If the application has
accidentally been configured with a zero length server list, and has
accidentally passed that zero length server list in the client/client_len
parameters, and has additionally failed to correctly handle a "no overlap"
response (which would normally result in a handshake failure in ALPN) then it
will be vulnerable to this problem.
In the case of NPN, the protocol permits the client to opportunistically select
a protocol when there is no overlap. OpenSSL returns the first client protocol
in the no overlap case in support of this. The list of client protocols comes
from the application and should never normally be expected to be of zero length.
However if the SSL_select_next_proto function is accidentally called with a
client_len of 0 then an invalid memory pointer will be returned instead. If the
application uses this output as the opportunistic protocol then the loss of
confidentiality will occur.
This issue has been assessed as Low severity because applications are most
likely to be vulnerable if they are using NPN instead of ALPN - but NPN is not
widely used. It also requires an application configuration or programming error.
Finally, this issue would not typically be under attacker control making active
exploitation unlikely.
The FIPS modules in 3.3, 3.2, 3.1 and 3.0 are not affected by this issue.
Due to the low severity of this issue we are not issuing new releases of
OpenSSL at this time. The fix will be included in the next releases when they
become available. |
