libcurl might in some circumstances reuse the wrong connection for SMB(S)
transfers.

libcurl features a pool of recent connections so that subsequent requests can
reuse an existing connection to avoid overhead.

When reusing a connection a range of criteria must be met. Due to a logical
error in the code, a network transfer operation that was requested by an
application could wrongfully reuse an existing SMB connection to the same
server that was using a different 'share' than the new subsequent transfer
should.

This could in unlucky situations lead to the download of the wrong file or the
upload of a file to the wrong place. When this happens, the same credentials
are used and the server name is the same.

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact None

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00018.

Exploitation poc

Automatable yes

Technical Impact partial

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
curl curl unaffected
Version Status Constraints
8.19.0 affected ≤ 8.19.0
8.18.0 affected ≤ 8.18.0
8.17.0 affected ≤ 8.17.0
8.16.0 affected ≤ 8.16.0
8.15.0 affected ≤ 8.15.0
8.14.1 affected ≤ 8.14.1
8.14.0 affected ≤ 8.14.0
8.13.0 affected ≤ 8.13.0
8.12.1 affected ≤ 8.12.1
8.12.0 affected ≤ 8.12.0
8.11.1 affected ≤ 8.11.1
8.11.0 affected ≤ 8.11.0
8.10.1 affected ≤ 8.10.1
8.10.0 affected ≤ 8.10.0
8.9.1 affected ≤ 8.9.1
8.9.0 affected ≤ 8.9.0
8.8.0 affected ≤ 8.8.0
8.7.1 affected ≤ 8.7.1
8.7.0 affected ≤ 8.7.0
8.6.0 affected ≤ 8.6.0
8.5.0 affected ≤ 8.5.0
8.4.0 affected ≤ 8.4.0
8.3.0 affected ≤ 8.3.0
8.2.1 affected ≤ 8.2.1
8.2.0 affected ≤ 8.2.0
8.1.2 affected ≤ 8.1.2
8.1.1 affected ≤ 8.1.1
8.1.0 affected ≤ 8.1.0
8.0.1 affected ≤ 8.0.1
8.0.0 affected ≤ 8.0.0
7.88.1 affected ≤ 7.88.1
7.88.0 affected ≤ 7.88.0
7.87.0 affected ≤ 7.87.0
7.86.0 affected ≤ 7.86.0
7.85.0 affected ≤ 7.85.0
7.84.0 affected ≤ 7.84.0
7.83.1 affected ≤ 7.83.1
7.83.0 affected ≤ 7.83.0
7.82.0 affected ≤ 7.82.0
7.81.0 affected ≤ 7.81.0
7.80.0 affected ≤ 7.80.0
7.79.1 affected ≤ 7.79.1
7.79.0 affected ≤ 7.79.0
7.78.0 affected ≤ 7.78.0
7.77.0 affected ≤ 7.77.0
7.76.1 affected ≤ 7.76.1
7.76.0 affected ≤ 7.76.0
7.75.0 affected ≤ 7.75.0
7.74.0 affected ≤ 7.74.0
7.73.0 affected ≤ 7.73.0
7.72.0 affected ≤ 7.72.0
7.71.1 affected ≤ 7.71.1
7.71.0 affected ≤ 7.71.0
7.70.0 affected ≤ 7.70.0
7.69.1 affected ≤ 7.69.1
7.69.0 affected ≤ 7.69.0
7.68.0 affected ≤ 7.68.0
7.67.0 affected ≤ 7.67.0
7.66.0 affected ≤ 7.66.0
7.65.3 affected ≤ 7.65.3
7.65.2 affected ≤ 7.65.2
7.65.1 affected ≤ 7.65.1
7.65.0 affected ≤ 7.65.0
7.64.1 affected ≤ 7.64.1
7.64.0 affected ≤ 7.64.0
7.63.0 affected ≤ 7.63.0
7.62.0 affected ≤ 7.62.0
7.61.1 affected ≤ 7.61.1
7.61.0 affected ≤ 7.61.0
7.60.0 affected ≤ 7.60.0
7.59.0 affected ≤ 7.59.0
7.58.0 affected ≤ 7.58.0
7.57.0 affected ≤ 7.57.0
7.56.1 affected ≤ 7.56.1
7.56.0 affected ≤ 7.56.0
7.55.1 affected ≤ 7.55.1
7.55.0 affected ≤ 7.55.0
7.54.1 affected ≤ 7.54.1
7.54.0 affected ≤ 7.54.0
7.53.1 affected ≤ 7.53.1
7.53.0 affected ≤ 7.53.0
7.52.1 affected ≤ 7.52.1
7.52.0 affected ≤ 7.52.0
7.51.0 affected ≤ 7.51.0
7.50.3 affected ≤ 7.50.3
7.50.2 affected ≤ 7.50.2
7.50.1 affected ≤ 7.50.1
7.50.0 affected ≤ 7.50.0
7.49.1 affected ≤ 7.49.1
7.49.0 affected ≤ 7.49.0
7.48.0 affected ≤ 7.48.0
7.47.1 affected ≤ 7.47.1
7.47.0 affected ≤ 7.47.0
7.46.0 affected ≤ 7.46.0
7.45.0 affected ≤ 7.45.0
7.44.0 affected ≤ 7.44.0
7.43.0 affected ≤ 7.43.0
7.42.1 affected ≤ 7.42.1
7.42.0 affected ≤ 7.42.0
7.41.0 affected ≤ 7.41.0
7.40.0 affected ≤ 7.40.0

Configuration 1 [-]

cpe:2.3:a:haxx:curl:*:*:*:*:*:*:*:*

No data.

OpenCVE Enrichment is a feature of OpenCVE that uses AI to automatically link vendors and products to CVEs. Learn more on GitHub.

Vendors Products
Curl Subscribe
Libcurl Subscribe

Project Subscriptions

Vendors Products
Curl Subscribe
Libcurl Subscribe
Haxx Subscribe
Curl Subscribe
Advisories
Source ID Title
Ubuntu USN Ubuntu USN USN-8227-1 curl vulnerabilities
Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
http://www.openwall.com/lists/oss-security/2026/04/29/9 cve-icon
https://curl.se/docs/CVE-2026-5773.html cve-icon cve-icon cve-icon
https://curl.se/docs/CVE-2026-5773.json cve-icon cve-icon
https://hackerone.com/reports/3650689 cve-icon cve-icon cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2026-5773 cve-icon
https://www.cve.org/CVERecord?id=CVE-2026-5773 cve-icon
History

Wed, 13 May 2026 19:15:00 +0000

Type Values Removed Values Added
First Time appeared Haxx
Haxx curl
Weaknesses CWE-918
CPEs cpe:2.3:a:haxx:curl:*:*:*:*:*:*:*:*
Vendors & Products Haxx
Haxx curl

Wed, 13 May 2026 18:30:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N'}

 ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N'}

Wed, 13 May 2026 15:30:00 +0000

Type Values Removed Values Added
References

Wed, 13 May 2026 09:15:00 +0000

Type Values Removed Values Added
Description A flaw was found in libcurl. Due to a logical error in the connection reuse mechanism for SMB (Server Message Block) transfers, libcurl might reuse an existing SMB connection with a different share than intended. This vulnerability, categorized as CWE-488 (Exposure of Data Element to Wrong Session), could lead to the download of an incorrect file or the upload of a file to an unintended location when an application uses libcurl for SMB transfers. libcurl might in some circumstances reuse the wrong connection for SMB(S) transfers. libcurl features a pool of recent connections so that subsequent requests can reuse an existing connection to avoid overhead. When reusing a connection a range of criteria must be met. Due to a logical error in the code, a network transfer operation that was requested by an application could wrongfully reuse an existing SMB connection to the same server that was using a different 'share' than the new subsequent transfer should. This could in unlucky situations lead to the download of the wrong file or the upload of a file to the wrong place. When this happens, the same credentials are used and the server name is the same.
Title curl: libcurl: Wrong file transfer due to incorrect SMB connection reuse wrong reuse of SMB connection
References

Fri, 01 May 2026 01:45:00 +0000

Type Values Removed Values Added
First Time appeared Curl
Curl libcurl
Vendors & Products Curl
Curl libcurl

Fri, 01 May 2026 00:15:00 +0000

Type Values Removed Values Added
Description A flaw was found in libcurl. Due to a logical error in the connection reuse mechanism for SMB (Server Message Block) transfers, libcurl might reuse an existing SMB connection with a different share than intended. This vulnerability, categorized as CWE-488 (Exposure of Data Element to Wrong Session), could lead to the download of an incorrect file or the upload of a file to an unintended location when an application uses libcurl for SMB transfers.
Title curl: libcurl: Wrong file transfer due to incorrect SMB connection reuse
Weaknesses CWE-1025
References
Metrics threat_severity

None

 cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N'}

threat_severity

Moderate

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: curl

Published:

Updated: 2026-05-13T17:45:08.173Z

Reserved: 2026-04-08T06:51:05.356Z

Link: CVE-2026-5773

cve-icon Vulnrichment

Updated: 2026-05-13T09:05:23.608Z

cve-icon NVD

Status : Analyzed

Published: 2026-05-13T13:01:56.307

Modified: 2026-05-13T19:13:14.097

Link: CVE-2026-5773

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-04-29T00:00:00Z

Links: CVE-2026-5773 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-05-13T10:30:16Z

Weaknesses