SB20260720116 - Time-of-check Time-of-use (TOCTOU) Race Condition in Linux kernel block driver

Description

This security bulletin contains information about 1 vulnerability.

1) Time-of-check Time-of-use (TOCTOU) Race Condition (CVE-ID: CVE-2026-64112)

CWE-ID: CWE-367 - Time-of-check Time-of-use (TOCTOU) Race Condition

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 a time-of-check time-of-use race condition in the rbd lock_dwork handling in drivers/block/rbd.c when unmapping an image while exclusive lock work is being queued. A local user can trigger image unmap operations during concurrent I/O activity to cause a denial of service.

The issue can result in lock acquisition work executing after device and image release operations have freed or reset internal state.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/3427d7ae38337066ce88b68302e285d344ab756b
• https://git.kernel.org/stable/c/9400efc76b42c751211974a25c91d2c19c65b01b
• https://git.kernel.org/stable/c/9dcd4f5c99b491c37be90b0bd9988db48225fb75
• https://git.kernel.org/stable/c/9fc75b71fdd38465c76c6f6a884cdd4ae3c72d90