Known exploited vulnerability
CVE-2024-36971
The short answer
CVE-2024-36971 affects Linux Linux and is rated high (CVSS 7.8). CISA added it to the Known Exploited Vulnerabilities catalog on 2024-08-07: attackers are using it, so patch it first. The vendor has linked a patch.
What it is
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.
Weakness: CWE-416.
Severity
7.8 high
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Exploited (CISA KEV)
Yes, since Aug 7, 2024
Federal due date Aug 28, 2024
EPSS, next 30 days
2.7%
Higher than 86% of scored CVEs
How it can be exploited
- Attack vector
- Local
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
What CISA says to do
Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Affected products
Linux, linux_kernel. NVD's record lists the exact affected versions.
References
- git.kernel.org/stable/c/051c0bde9f0450a2ec3d62a86d2a0d2fad117f13 Patch
- git.kernel.org/stable/c/2295a7ef5c8c49241bff769e7826ef2582e532a6 Patch
- git.kernel.org/stable/c/5af198c387128a9d2ddd620b0f0803564a4d4508 Patch
- git.kernel.org/stable/c/81dd3c82a456b0015461754be7cb2693991421b4 Patch
- git.kernel.org/stable/c/92f1655aa2b2294d0b49925f3b875a634bd3b59e Patch
- git.kernel.org/stable/c/b8af8e6118a6605f0e495a58d591ca94a85a50fc Patch
- git.kernel.org/stable/c/db0082825037794c5dba9959c9de13ca34cc5e72 Patch
- git.kernel.org/stable/c/eacb8b195579c174a6d3e12a9690b206eb7f28cf Patch
- git.kernel.org/stable/c/051c0bde9f0450a2ec3d62a86d2a0d2fad117f13 Patch
- git.kernel.org/stable/c/2295a7ef5c8c49241bff769e7826ef2582e532a6 Patch
- git.kernel.org/stable/c/5af198c387128a9d2ddd620b0f0803564a4d4508 Patch
- git.kernel.org/stable/c/81dd3c82a456b0015461754be7cb2693991421b4 Patch
Questions
Is CVE-2024-36971 being exploited?
Yes. CISA added CVE-2024-36971 to its Known Exploited Vulnerabilities catalog on 2024-08-07, with a federal remediation due date of 2024-08-28.
How do I fix CVE-2024-36971?
CISA's required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
From NVD, CISA KEV, FIRST EPSS and OSV.dev, checked . Status on NVD: Analyzed. The description is NVD's text, quoted as published.
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