Linux Kernel up to 6.10-rc1 __dst_negative_advice use after free

Summaryinfo

A vulnerability labeled as critical has been found in Linux Kernel up to 6.10-rc1. The impacted element is the function __dst_negative_advice. The manipulation results in use after free. This vulnerability was named CVE-2024-36971. The attack needs to be approached locally. In addition, an exploit is available. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.10-rc1. It has been classified as critical. Affected is the function __dst_negative_advice. The manipulation with an unknown input leads to a use after free vulnerability. CWE is classifying the issue as CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

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.

The weakness was presented by Clement Lecigne. The advisory is shared for download at git.kernel.org. This vulnerability is traded as CVE-2024-36971 since 05/30/2024. The exploitability is told to be difficult. The attack needs to be approached locally. Technical details and a exploit are known. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 12/04/2025).

It is declared as attacked. The vulnerability scanner Nessus provides a plugin with the ID 207738 (Ubuntu 20.04 LTS : Linux kernel vulnerabilities (USN-7009-2)), which helps to determine the existence of the flaw in a target environment. This issue was added on 08/07/2024 to the CISA Known Exploited Vulnerabilities Catalog with a due date of 08/28/2024:

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

Upgrading to version 6.10-rc2 eliminates this vulnerability. Applying the patch 92f1655aa2b2 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Zero-Day.cz (897), Tenable (207738) and CERT Bund (WID-SEC-2025-1293). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Affected

• Ubuntu Linux
• IBM DataPower Gateway

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.10-rc1

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

• 🔍
• 🔍

CPE 2.2info

• 🔍
• 🔍

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

VulDB is the best source for vulnerability data and more expert information about this specific topic.

Discussion