USB: serial: kl5kusb105: fix bulk-out buffer overflow
Summary
| CVE | CVE-2026-53194 |
|---|---|
| State | PUBLISHED |
| Assigner | Linux |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-06-25 09:16:36 UTC |
| Updated | 2026-07-15 01:16:30 UTC |
| 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. |
Risk And Classification
Primary CVSS: v3.1 5.3 MEDIUM from ADP
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:H
EPSS: 0.001460000 probability, percentile 0.042120000 (date 2026-07-04)
Problem Types: CWE-787 | CWE-787 Out-of-bounds Write
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | ADP | CVSS | 5.3 | MEDIUM | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:H |
| 3.1 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | Secondary | 7.8 | HIGH | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| 3.1 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | Secondary | 5.3 | MEDIUM | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:H |
| 3.1 | CNA | DECLARED | 7.8 | HIGH | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
CVSS v3.1 Breakdown
Attack Vector
LocalAttack Complexity
HighPrivileges Required
LowUser Interaction
NoneScope
UnchangedConfidentiality
NoneIntegrity
LowAvailability
HighCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:H
NVD Known Affected Configurations (CPE 2.3)
| Type | Vendor | Product | Version | Update | Edition | Language |
|---|---|---|---|---|---|---|
| Operating System | Linux | Linux Kernel | All | All | All | All |
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Linux | Linux | affected 60b3013cdaf3fa8a17243ca46b19db3cbe08d943 60af1fd82983c26604102e63a3fcc822c186cceb git | Not specified |
| CNA | Linux | Linux | affected 60b3013cdaf3fa8a17243ca46b19db3cbe08d943 0a57320f71941d4e0b1307453c9a1f0939afe666 git | Not specified |
| CNA | Linux | Linux | affected 60b3013cdaf3fa8a17243ca46b19db3cbe08d943 14147b7963685957839c76ba8094924e22777d79 git | Not specified |
| CNA | Linux | Linux | affected 60b3013cdaf3fa8a17243ca46b19db3cbe08d943 a1288cd700f721c1a119c4f1e8efa234e59caada git | Not specified |
| CNA | Linux | Linux | affected 60b3013cdaf3fa8a17243ca46b19db3cbe08d943 70d86e355c564b5510fde61361df014f5476c83e git | Not specified |
| CNA | Linux | Linux | affected 60b3013cdaf3fa8a17243ca46b19db3cbe08d943 372f33ebed747d91870f57c0a2e62884a870bffa git | Not specified |
| CNA | Linux | Linux | affected 60b3013cdaf3fa8a17243ca46b19db3cbe08d943 bde742b076cbe26ecc89c8c68c76ae076a524d02 git | Not specified |
| CNA | Linux | Linux | affected 60b3013cdaf3fa8a17243ca46b19db3cbe08d943 96d47e40bf9db4a9efd5c8fb53287a508d165f14 git | Not specified |
| CNA | Linux | Linux | affected 2.6.35 | Not specified |
| CNA | Linux | Linux | unaffected 2.6.35 semver | Not specified |
| CNA | Linux | Linux | unaffected 5.10.259 5.10.* semver | Not specified |
| CNA | Linux | Linux | unaffected 5.15.210 5.15.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.1.176 6.1.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.6.143 6.6.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.12.94 6.12.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.18.36 6.18.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.0.13 7.0.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.1 * original_commit_for_fix | Not specified |
| ADP | Red Hat | Red Hat Enterprise Linux 10 | Not specified | Not specified |
| ADP | Red Hat | Red Hat Enterprise Linux 6 | Not specified | Not specified |
| ADP | Red Hat | Red Hat Enterprise Linux 7 | Not specified | Not specified |
| ADP | Red Hat | Red Hat Enterprise Linux 7 | Not specified | Not specified |
| ADP | Red Hat | Red Hat Enterprise Linux 8 | Not specified | Not specified |
| ADP | Red Hat | Red Hat Enterprise Linux 8 | Not specified | Not specified |
| ADP | Red Hat | Red Hat Enterprise Linux 9 | Not specified | Not specified |
| ADP | Red Hat | Red Hat Enterprise Linux 9 | Not specified | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| git.kernel.org/stable/c/0a57320f71941d4e0b1307453c9a1f0939afe666 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | Patch |
| git.kernel.org/stable/c/60af1fd82983c26604102e63a3fcc822c186cceb | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | Patch |
| access.redhat.com/security/cve/CVE-2026-53194 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | Third Party Advisory |
| security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-53194.json | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | security.access.redhat.com | Third Party Advisory |
| git.kernel.org/stable/c/372f33ebed747d91870f57c0a2e62884a870bffa | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | Patch |
| git.kernel.org/stable/c/96d47e40bf9db4a9efd5c8fb53287a508d165f14 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | Patch |
| bugzilla.redhat.com/show_bug.cgi | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | bugzilla.redhat.com | Issue Tracking, Third Party Advisory |
| git.kernel.org/stable/c/14147b7963685957839c76ba8094924e22777d79 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | Patch |
| git.kernel.org/stable/c/a1288cd700f721c1a119c4f1e8efa234e59caada | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | Patch |
| git.kernel.org/stable/c/bde742b076cbe26ecc89c8c68c76ae076a524d02 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | Patch |
| git.kernel.org/stable/c/70d86e355c564b5510fde61361df014f5476c83e | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | Patch |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| ADP | 2026-06-25T00:00:00.000Z | Reported to Red Hat. |
| ADP | 2026-06-25T00:00:00.000Z | Made public. |
Workarounds
ADP: To mitigate this issue, prevent module kl5kusb105 from being loaded. Please see https://access.redhat.com/solutions/41278 for how to blacklist a kernel module to prevent it from loading automatically.
There are currently no legacy QID mappings associated with this CVE.