SB20260918348 - Use-after-free in Linux kernel blk-cgroup policy activation rollback path

Description

This security bulletin contains information about 1 vulnerability.

1) Use-after-free (CVE-ID: CVE-2026-90326)

CWE-ID: CWE-416 - Use After Free

CVSSv4: 2 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]

The vulnerability allows a local user to cause memory corruption.

The vulnerability exists due to a race condition leading to use-after-free in the blk-cgroup policy activation rollback path when rolling back policy-data allocation during concurrent block cgroup deletion. A local user can trigger concurrent I/O scheduler switching and block cgroup deletion to cause memory corruption.

The race requires policy-data allocation to fail during policy activation.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/083b58373463a6e5ee60ecb135269348f68ad7df
• https://git.kernel.org/stable/c/2cf9f50a38c1839e549a08e22aa35e8d69e2c8fd
• https://git.kernel.org/stable/c/5313d4d41739b0cb63000747c97bb1217ac45f3e
• https://git.kernel.org/stable/c/ac34e655dffa74349d885a43d098115336f53842
• https://git.kernel.org/stable/c/b5dae1cd0d8368b4338430ff93403df67f0b8bcc