High [CVE-2026-74305] Tighten cgroup storage cookie checks for prog arrays
This high-severity Red Hat Linux advisory covers CVE-2026-74305 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat package: kernel.
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Summary
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. A flaw was found in the Linux kernel's Berkeley Packet Filter (BPF) subsystem.
This vulnerability allows a program without cgroup storage to bypass compatibility checks when bridging tail call chains. This could enable unintended interactions between programs with and without cgroup storage, potentially leading to a security bypass.
Red Hat severity: Moderate — CVSS 7 (CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H). Weakness: CWE-358.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · medium-confidence parse· fetched 1 hour ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · medium-confidence parse· fetched 1 hour ago·verify at source
Mitigation
The source record does not include mitigation steps. That is not a statement that no fix exists — read the vendor advisory below for the authoritative guidance.
Official advisory · medium-confidence parse· fetched 1 hour ago·verify at source
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