Out-of-bounds write in Linux kernel - CVE-2026-63825

Vulnerability details

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.

Affected software

How to mitigate CVE-2026-63825

External References

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

Related Security Bulletins

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