Linux Kernel up to 6.16.9 futex futex_hash_allocate_default allocation of resources

Summaryinfo

A vulnerability classified as critical has been found in Linux Kernel up to 6.16.9. Affected is the function futex_hash_allocate_default of the component futex. Performing a manipulation results in allocation of resources. This vulnerability is known as CVE-2025-39976. No exploit is available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical has been found in Linux Kernel up to 6.16.9. This affects the function futex_hash_allocate_default of the component futex. The manipulation with an unknown input leads to a allocation of resources vulnerability. CWE is classifying the issue as CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. The impact remains unknown. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: futex: Use correct exit on failure from futex_hash_allocate_default() copy_process() uses the wrong error exit path from futex_hash_allocate_default(). After exiting from futex_hash_allocate_default(), neither tasklist_lock nor siglock has been acquired. The exit label bad_fork_core_free unlocks both of these locks which is wrong. The next exit label, bad_fork_cancel_cgroup, is the correct exit. sched_cgroup_fork() did not allocate any resources that need to freed. Use bad_fork_cancel_cgroup on error exit from futex_hash_allocate_default().

It is possible to read the advisory at git.kernel.org. This vulnerability is uniquely identified as CVE-2025-39976 since 04/16/2025. Technical details of the vulnerability are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 271543 (Linux Distros Unpatched Vulnerability : CVE-2025-39976), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.16.10 eliminates this vulnerability. Applying the patch f1635765cd0fdbf27b04d9a50be91a01b5adda13/4ec3c15462b9f44562f45723a92e2807746ba7d1 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 (271543) and CERT Bund (WID-SEC-2025-2298). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Affected

• Google Container-Optimized OS
• Debian Linux
• Amazon Linux 2
• Red Hat Enterprise Linux
• Ubuntu Linux
• SUSE Linux
• Oracle Linux
• SUSE openSUSE
• RESF Rocky Linux
• Open Source Linux Kernel
• IBM QRadar SIEM
• Dell NetWorker

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.16.0
• 6.16.1
• 6.16.2
• 6.16.3
• 6.16.4
• 6.16.5
• 6.16.6
• 6.16.7
• 6.16.8
• 6.16.9

License

• open-source

Website

• Vendor: https://www.kernel.org/

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