# CVE-2024-36971

In the Linux kernel, the following vulnerability has been resolved: net: fix __dst_negative_advice() race __dst_negative_advice() does not enforce proper RCU rules when sk->dst_cache must be cleared, leading to possible UAF. RCU rules are that we must first clear sk->sk_dst_cache, then call dst_release(old_dst). Note that sk_dst_reset(sk) is implementing this protocol correctly, while __dst_negative_advice() uses the wrong order. Given that ip6_negative_advice() has special logic against RTF_CACHE, this means each of the three ->negative_advice() existing methods must perform the sk_dst_reset() themselves. Note the check against NULL dst is centralized in __dst_negative_advice(), there is no need to duplicate it in various callbacks. Many thanks to Clement Lecigne for tracking this issue. This old bug became visible after the blamed commit, using UDP sockets.

- Page: https://www.vulneraibility.com/cve/CVE-2024-36971
- CVSS: 7.8
- Known exploited: yes, in CISA KEV since 2024-08-07; CISA due date 2024-08-28
- EPSS: 2.70% (percentile 86.1)
- Unvetted proof-of-concept code on GitHub: 1 GitHub proof of concept (first 2025-10-14)
- CISA SSVC: exploitation active, automatable no, technical impact total (assessed 2024-08-08)
- Weakness: CWE-416
- Published: 2024-06-10

## Affected versions

- Linux: affected >= a87cb3e48ee86d29868d3f59cfb9ce1a8fa63314 and < 051c0bde9f0450a2ec3d62a86d2a0d2fad117f13; >= a87cb3e48ee86d29868d3f59cfb9ce1a8fa63314 and < db0082825037794c5dba9959c9de13ca34cc5e72; >= a87cb3e48ee86d29868d3f59cfb9ce1a8fa63314 and < 2295a7ef5c8c49241bff769e7826ef2582e532a6; >= a87cb3e48ee86d29868d3f59cfb9ce1a8fa63314 and < eacb8b195579c174a6d3e12a9690b206eb7f28cf; >= a87cb3e48ee86d29868d3f59cfb9ce1a8fa63314 and < 81dd3c82a456b0015461754be7cb2693991421b4; >= a87cb3e48ee86d29868d3f59cfb9ce1a8fa63314 and < 5af198c387128a9d2ddd620b0f0803564a4d4508; >= a87cb3e48ee86d29868d3f59cfb9ce1a8fa63314 and < b8af8e6118a6605f0e495a58d591ca94a85a50fc; >= a87cb3e48ee86d29868d3f59cfb9ce1a8fa63314 and < 92f1655aa2b2294d0b49925f3b875a634bd3b59e; 4.6; fixed in < 4.6, >= 4.19.316 and <= 4.19.*, >= 5.4.278 and <= 5.4.*, >= 5.10.219 and <= 5.10.*, >= 5.15.161 and <= 5.15.*, >= 6.1.94 and <= 6.1.*, >= 6.6.34 and <= 6.6.*, >= 6.9.4 and <= 6.9.*, >= 6.10 and <= *

A version outside these ranges is not a statement that it is unaffected.

## References

- [other] https://git.kernel.org/stable/c/051c0bde9f0450a2ec3d62a86d2a0d2fad117f13
- [other] https://git.kernel.org/stable/c/db0082825037794c5dba9959c9de13ca34cc5e72
- [other] https://git.kernel.org/stable/c/2295a7ef5c8c49241bff769e7826ef2582e532a6
- [other] https://git.kernel.org/stable/c/eacb8b195579c174a6d3e12a9690b206eb7f28cf
- [other] https://git.kernel.org/stable/c/81dd3c82a456b0015461754be7cb2693991421b4
- [other] https://git.kernel.org/stable/c/5af198c387128a9d2ddd620b0f0803564a4d4508
- [other] https://git.kernel.org/stable/c/b8af8e6118a6605f0e495a58d591ca94a85a50fc
- [other] https://git.kernel.org/stable/c/92f1655aa2b2294d0b49925f3b875a634bd3b59e
- [other] https://lists.debian.org/debian-lts-announce/2024/06/msg00020.html
- [other] https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2024-36971

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Summary, impact and action are written by the vulneraibility.com AI analysis pipeline from the CVE record, NVD, CISA and FIRST data; verify against the references.