CVE-2024-36971

net: fix __dst_negative_advice() race

High 7.8
Exploited: added to CISA KEV 7 Aug 2024

Description

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.

Key facts

Published: 10 Jun 2024
Last changed: 5 Aug 2026
Assigned by: Linux
KEV added: 7 Aug 2024
KEV fix due: 28 Aug 2024
EPSS: 2.701% likely to be exploited in the next 30 days, higher than 86.173% of CVEs (scores for 15 Nov 2026)
SSVC (CISA): Exploitation: active; Automatable: no; Technical impact: total

Severity scores

Each score is shown as its source gave it. They are not averaged or merged.

7.8CVSS 3.1, Highfrom the CNA (Linux)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.8CVSS 3.1, Highfrom CISA (ADP container)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

What to do

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.CISA KEV required action

Historical context and remediation

This reference retains the original CVE publication date. A recent record update does not mean a new attack occurred.

No separately sourced impact summary is available on this page yet. Consult the description, version data and dated exploitation evidence.

Version statuses below come from the CNA. An “unaffected” version is not necessarily a currently supported release or proof of a patch date. EPSS is a dated risk estimate, not a count of historical attacks.

Read the original CVE record.

Affected products

Vendor	Product	Versions
Linux	Linux	Default status: unaffected a87cb3e48ee86d29868d3f59cfb9ce1a8fa63314 up to but excluding 051c0bde9f0450a2ec3d62a86d2a0d2fad117f13 (affected) a87cb3e48ee86d29868d3f59cfb9ce1a8fa63314 up to but excluding db0082825037794c5dba9959c9de13ca34cc5e72 (affected) a87cb3e48ee86d29868d3f59cfb9ce1a8fa63314 up to but excluding 2295a7ef5c8c49241bff769e7826ef2582e532a6 (affected) a87cb3e48ee86d29868d3f59cfb9ce1a8fa63314 up to but excluding eacb8b195579c174a6d3e12a9690b206eb7f28cf (affected) a87cb3e48ee86d29868d3f59cfb9ce1a8fa63314 up to but excluding 81dd3c82a456b0015461754be7cb2693991421b4 (affected) a87cb3e48ee86d29868d3f59cfb9ce1a8fa63314 up to but excluding 5af198c387128a9d2ddd620b0f0803564a4d4508 (affected) a87cb3e48ee86d29868d3f59cfb9ce1a8fa63314 up to but excluding b8af8e6118a6605f0e495a58d591ca94a85a50fc (affected) a87cb3e48ee86d29868d3f59cfb9ce1a8fa63314 up to but excluding 92f1655aa2b2294d0b49925f3b875a634bd3b59e (affected)
Linux	Linux	Default status: affected 4.6 (affected) 0 up to but excluding 4.6 (unaffected) 4.19.316 up to and including 4.19.* (unaffected) 5.4.278 up to and including 5.4.* (unaffected) 5.10.219 up to and including 5.10.* (unaffected) 5.15.161 up to and including 5.15.* (unaffected) 6.1.94 up to and including 6.1.* (unaffected) 6.6.34 up to and including 6.6.* (unaffected) 6.9.4 up to and including 6.9.* (unaffected) 6.10 up to and including * (unaffected)