# 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.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **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:** Yes
- **Published:** 15 Aug 2026
- **Updated:** 16 Oct 2026
- **Also known as:** BELL-CVE-2026-74305, DEBIAN-CVE-2026-74305, GHSA-7p9j-gmgx-g4fv, UBUNTU-CVE-2026-74305

## 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.

## Is CVE-2026-74305 being exploited?

There is no known exploitation of CVE-2026-74305 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74305 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-74305 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-74305/ (Markdown: https://insights.sbomify.com/CVE-2026-74305/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74305
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74305
- OSV: https://osv.dev/vulnerability/CVE-2026-74305

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74305/
Summaries are generated and may contain mistakes; the official description above is the record.