CVE-2026-74305

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

bpf: Tighten cgroup storage cookie checks for prog arrays

The fix in commit abad3d0bad72 ("bpf: Fix oob access in cgroup local

storage") is still incomplete. The prog-array compatibility check

treats a program with no cgroup storage as compatible with any stored

storage cookie. This allows a storage-less program to bridge a tail

call chain between an entry program and a storage-using callee even

though cgroup local storage at runtime still follows the caller's

context, that is, A -> B(no storage) -> C(storage) path.

Requiring exact cookie equality would break the legitimate case of a

storage-less leaf program being tail called from a storage-using one.

Instead, only accept a zero storage cookie if the program cannot

perform tail calls itself. This keeps A -> B(no storage) working

while rejecting the A -> B(no storage) -> C(storage) bridge.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References