Linux Kernel up to 7.2.12 sched_ext run_deferred use after free

Summaryinfo

A vulnerability categorized as very critical has been discovered in Linux Kernel up to 7.2.12. Affected by this issue is the function run_deferred of the component sched_ext. The manipulation results in use after free. This vulnerability is known as CVE-2026-99144. It is possible to launch the attack remotely. No exploit is available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as very critical, was found in Linux Kernel up to 7.2.12. Affected is the function run_deferred of the component sched_ext. 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: sched_ext: Fix use-after-free of a destroyed user DSQ by a deferred reenqueue A deferred reenqueue can read a freed user DSQ. The request stays on its CPU's deferred list until run_deferred() takes it, and the RCU callback that frees the DSQ assumes that the grace period has flushed it, so exit_dsq() checks the per-CPU node without the deferred list lock. A grace period waits for readers in flight, not for a pending run_deferred(). A run_deferred() which starts after the grace period began can detach the request right before the callback looks and then read the freed DSQ's id. Cancel the pending requests before the grace period instead. The irq work that frees the DSQ unlinks every CPU's request under the per-CPU deferred list lock, and schedule_dsq_reenq() ignores a new request under the same lock once the id is invalid. Only a run_deferred() that started before the grace period can hold a request, and it runs with IRQs disabled, so the grace period waits for it and nothing touches the DSQ after the callback.

The advisory is available at git.kernel.org. This vulnerability is traded as CVE-2026-99144 since 09/25/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $5k-$25k at the moment (estimation calculated on 10/28/2026).

Upgrading to version 7.2.13 eliminates this vulnerability. Applying the patch 633f586329bfd9843bf8acf86c95353f4c16e22d/069403dff337feb192bfc70fb28ddc8a171e20c1 is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 7.2.0
• 7.2.1
• 7.2.2
• 7.2.3
• 7.2.4
• 7.2.5
• 7.2.6
• 7.2.7
• 7.2.8
• 7.2.9
• 7.2.10
• 7.2.11
• 7.2.12

License

• open-source

Website

• Vendor: https://www.kernel.org/

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Entryinfo

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