SB2026072108 - Out-of-bounds write in Linux kernel inflate_fast()

Description

This security bulletin contains information about 1 vulnerability.

1) Out-of-bounds write (CVE-ID: CVE-2026-63825)

CWE-ID: CWE-787 - Out-of-bounds write

CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to an out-of-bounds write in inflate_fast() when processing IP payload compression data concurrently on multiple cpus. A local user can trigger concurrent execution of the vulnerable code path to cause a denial of service.

The issue occurs because global gcov counters can change between multiple loads during execution, producing inconsistent loop values.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/49d893b9cbcfc5802a32e53a64c6c6956670d65b
• https://git.kernel.org/stable/c/56cb9b7d96b28a1173a510ab25354b6599ad3a33
• https://git.kernel.org/stable/c/5b959c1dbb4522b9e3ac4e26ad638b8784869841