Linux Kernel dma-buf/dma-fence use after free

Summaryinfo

A vulnerability labeled as very critical has been found in Linux Kernel. This impacts an unknown function of the component dma-buf/dma-fence. Executing a manipulation can lead to use after free. The identification of this vulnerability is CVE-2026-98243. The attack may be launched remotely. There is no exploit available. It is best practice to apply a patch to resolve this issue.

Detailsinfo

A vulnerability was found in Linux Kernel (the affected version unknown). It has been declared as very critical. This vulnerability affects an unknown part of the component dma-buf/dma-fence. 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. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: dma-buf/dma-fence: fix checking signaling bit for timeline and driver name v3 The patch "dma-buf: dma-fence: Fix potential NULL pointer dereference" changed the check to test for the ops pointer instead of the signaled bit to avoid a potential NULL dereference when the ops pointer has been cleared. The problem is now that the ops pointer is cleared only when neither the release nor the wait callback is implemented and this isn't true for a lot of dma_fence implementations yet. So those implementations lost the RCU protection after signaling of the returned string resulting in potential use after free. Add the signaling check additional to the ops pointer check so that we have both the protection against NULL dereference as well as the RCU protection after signaling for the returned string. v2: improve comments to note RCU protection and explain why we check both signaling state and ops pointer v3: some comment improvements suggested by Philip

The advisory is available at git.kernel.org. This vulnerability was named CVE-2026-98243 since 09/25/2026. The exploitation appears to be easy. The attack can be initiated remotely. The technical details are unknown and an exploit is not available. The structure of the vulnerability defines a possible price range of USD $5k-$25k at the moment (estimation calculated on 10/06/2026).

Applying the patch a4db25b8949d6ff9c1a685a1273a015e8bab29db/3ed11c671ff7ec58c8fd96410233c677df23f407 is able to eliminate this problem.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

License

• open-source

Website

• Vendor: https://www.kernel.org/

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