Linux Kernel up to 6.6.x IPv4 net/ipv4/igmp.c igmp_start_timer use after free

Summaryinfo

A vulnerability identified as critical has been detected in Linux Kernel up to 6.6.x. This vulnerability affects the function igmp_start_timer of the file net/ipv4/igmp.c of the component IPv4 Handler. This manipulation causes use after free. This vulnerability appears as CVE-2023-6932. The attack requires local access. There is no available exploit. You should upgrade the affected component.

Detailsinfo

A vulnerability classified as critical was found in Linux Kernel up to 6.6.x (Operating System). Affected by this vulnerability is the function igmp_start_timer of the file net/ipv4/igmp.c of the component IPv4 Handler. The manipulation with an unknown input leads to a use after free vulnerability. The CWE definition for the vulnerability is CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

A use-after-free vulnerability in the Linux kernel's ipv4: igmp component can be exploited to achieve local privilege escalation. A race condition can be exploited to cause a timer be mistakenly registered on a RCU read locked object which is freed by another thread. We recommend upgrading past commit e2b706c691905fe78468c361aaabc719d0a496f1.

The weakness was presented 12/19/2023. It is possible to read the advisory at kernel.dance. This vulnerability is known as CVE-2023-6932 since 12/18/2023. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 11/25/2025).

The vulnerability scanner Nessus provides a plugin with the ID 239742 (TencentOS Server 2: kernel (TSSA-2024:1030)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.7 eliminates this vulnerability. Applying a patch 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 vulnerability database at Tenable (239742). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.0
• 6.1
• 6.2
• 6.3
• 6.4
• 6.5
• 6.6

License

• open-source

Website

• Vendor: https://www.kernel.org/

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Be aware that VulDB is the high quality source for vulnerability data.

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