CVE-2026-74305: bpf: Tighten cgroup storage cookie checks for prog arrays

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-15 · updated 2026-10-16

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.

Affected products

Linux kernel: from 5.15.192 before 5.15.212; from 6.1.151 before 6.1.178; from 6.6.105 before 6.6.145; from 6.12.46 before 6.12.97; from 6.16.1 before 6.17; 6.17 — fixed in 5.15.212, 6.1.178, 6.12.97, 6.17, 6.6.145, 7.2

How to fix

Upgrade to a fixed version: Linux kernel 5.15.212, 6.1.178, 6.12.97, 6.17. Check the vendor advisory for mitigations.

References

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