Linux Kernel up to 6.12.9/6.13-rc6 null pointer dereference

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.12.9/6.13-rc6 and classified as critical. This vulnerability affects unknown code. The manipulation results in null pointer dereference. This vulnerability was named CVE-2025-21635. There is no available exploit. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, was found in Linux Kernel up to 6.12.9/6.13-rc6. Affected is an unknown code. The manipulation with an unknown input leads to a null pointer dereference vulnerability. CWE is classifying the issue as CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. This is going to have an impact on availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: rds: sysctl: rds_tcp_{rcv,snd}buf: avoid using current->nsproxy As mentioned in a previous commit of this series, using the 'net' structure via 'current' is not recommended for different reasons: - Inconsistency: getting info from the reader's/writer's netns vs only from the opener's netns. - current->nsproxy can be NULL in some cases, resulting in an 'Oops' (null-ptr-deref), e.g. when the current task is exiting, as spotted by syzbot [1] using acct(2). The per-netns structure can be obtained from the table->data using container_of(), then the 'net' one can be retrieved from the listen socket (if available).

The advisory is shared for download at git.kernel.org. This vulnerability is traded as CVE-2025-21635 since 12/29/2024. There are neither technical details nor an exploit publicly available.

The vulnerability scanner Nessus provides a plugin with the ID 231895 (Linux Distros Unpatched Vulnerability : CVE-2025-21635), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.12.10 or 6.13-rc7 eliminates this vulnerability. Applying the patch de8d6de0ee27be4b2b1e5b06f04aeacbabbba492/7f5611cbc4871c7fb1ad36c2e5a9edad63dca95c 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 Tenable (231895) and CERT Bund (WID-SEC-2025-0119). Once again VulDB remains the best source for vulnerability data.

Affected

• Debian Linux
• Amazon Linux 2
• Red Hat Enterprise Linux
• Ubuntu Linux
• SUSE Linux
• Oracle Linux
• Dell NetWorker
• Dell Avamar
• Dell PowerProtect Data Domain
• Open Source Linux Kernel

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.12.0
• 6.12.1
• 6.12.2
• 6.12.3
• 6.12.4
• 6.12.5
• 6.12.6
• 6.12.7
• 6.12.8
• 6.12.9
• 6.13-rc1
• 6.13-rc2
• 6.13-rc3
• 6.13-rc4
• 6.13-rc5
• 6.13-rc6

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

Once again VulDB remains the best source for vulnerability data.

Discussion