CVE-2026-74305 bpf: Tighten cgroup storage cookie checks for prog arrays
A logic flaw in Linux kernel BPF cgroup storage checks allows bypassing security restrictions, potentially enabling privilege escalation or code execution.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-74305?
CVE-2026-74305 is a high-severity missing authorization vulnerability in Linux, published on 15 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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.
Which versions are affected by CVE-2026-74305?
How do I fix CVE-2026-74305?
Apply the vendor's patch.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-74305 being exploited?
There is no known exploitation of CVE-2026-74305 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-74305, DEBIAN-CVE-2026-74305, GHSA-7p9j-gmgx-g4fv, UBUNTU-CVE-2026-74305.