In the Linux kernel, the following vulnerability has been resolved:
USB: serial: kl5kusb105: fix bulk-out buffer overflow
klsi_105_prepare_write_buffer() is called by the generic write path
with the bulk-out buffer and its size (bulk_out_size, 64 bytes). It
stores a two-byte length header at the start of the buffer and copies
the payload from the write fifo starting at buf + KLSI_HDR_LEN, but
passes the full buffer size as the number of bytes to copy:
count = kfifo_out_locked(&port->write_fifo, buf + KLSI_HDR_LEN,
size, &port->lock);
When the fifo holds at least size bytes, size bytes are copied starting
two bytes into the size-byte buffer, writing KLSI_HDR_LEN bytes past its
end. Copy at most size - KLSI_HDR_LEN bytes instead, leaving room for
the header as safe_serial already does.
Writing bulk_out_size or more bytes to the tty triggers a slab
out-of-bounds write, observed with KASAN by emulating the device with
dummy_hcd and raw-gadget:
BUG: KASAN: slab-out-of-bounds in kfifo_copy_out+0x83/0xc0
Write of size 64 at addr ffff888112c62202 by task python3
kfifo_copy_out
klsi_105_prepare_write_buffer [kl5kusb105]
usb_serial_generic_write_start [usbserial]
Allocated by task 139:
usb_serial_probe [usbserial]
The buggy address is located 2 bytes inside of allocated 64-byte region
The out-of-bounds write no longer occurs with this change applied.
USB: serial: kl5kusb105: fix bulk-out buffer overflow
klsi_105_prepare_write_buffer() is called by the generic write path
with the bulk-out buffer and its size (bulk_out_size, 64 bytes). It
stores a two-byte length header at the start of the buffer and copies
the payload from the write fifo starting at buf + KLSI_HDR_LEN, but
passes the full buffer size as the number of bytes to copy:
count = kfifo_out_locked(&port->write_fifo, buf + KLSI_HDR_LEN,
size, &port->lock);
When the fifo holds at least size bytes, size bytes are copied starting
two bytes into the size-byte buffer, writing KLSI_HDR_LEN bytes past its
end. Copy at most size - KLSI_HDR_LEN bytes instead, leaving room for
the header as safe_serial already does.
Writing bulk_out_size or more bytes to the tty triggers a slab
out-of-bounds write, observed with KASAN by emulating the device with
dummy_hcd and raw-gadget:
BUG: KASAN: slab-out-of-bounds in kfifo_copy_out+0x83/0xc0
Write of size 64 at addr ffff888112c62202 by task python3
kfifo_copy_out
klsi_105_prepare_write_buffer [kl5kusb105]
usb_serial_generic_write_start [usbserial]
Allocated by task 139:
usb_serial_probe [usbserial]
The buggy address is located 2 bytes inside of allocated 64-byte region
The out-of-bounds write no longer occurs with this change applied.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
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| Linux | Linux | affected |
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Fixes
Solution
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Workaround
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References
History
Thu, 25 Jun 2026 11:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-122 |
Thu, 25 Jun 2026 09:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: USB: serial: kl5kusb105: fix bulk-out buffer overflow klsi_105_prepare_write_buffer() is called by the generic write path with the bulk-out buffer and its size (bulk_out_size, 64 bytes). It stores a two-byte length header at the start of the buffer and copies the payload from the write fifo starting at buf + KLSI_HDR_LEN, but passes the full buffer size as the number of bytes to copy: count = kfifo_out_locked(&port->write_fifo, buf + KLSI_HDR_LEN, size, &port->lock); When the fifo holds at least size bytes, size bytes are copied starting two bytes into the size-byte buffer, writing KLSI_HDR_LEN bytes past its end. Copy at most size - KLSI_HDR_LEN bytes instead, leaving room for the header as safe_serial already does. Writing bulk_out_size or more bytes to the tty triggers a slab out-of-bounds write, observed with KASAN by emulating the device with dummy_hcd and raw-gadget: BUG: KASAN: slab-out-of-bounds in kfifo_copy_out+0x83/0xc0 Write of size 64 at addr ffff888112c62202 by task python3 kfifo_copy_out klsi_105_prepare_write_buffer [kl5kusb105] usb_serial_generic_write_start [usbserial] Allocated by task 139: usb_serial_probe [usbserial] The buggy address is located 2 bytes inside of allocated 64-byte region The out-of-bounds write no longer occurs with this change applied. | |
| Title | USB: serial: kl5kusb105: fix bulk-out buffer overflow | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
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Projects
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MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-06-25T08:39:05.017Z
Reserved: 2026-06-09T07:44:35.390Z
Link: CVE-2026-53194
Vulnrichment
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NVD
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Redhat
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OpenCVE Enrichment
Updated: 2026-06-25T11:00:11Z
Weaknesses