CVE-2026-93042 dmaengine: dw-edma: Terminate all descriptors without callbacks
A use-after-free vulnerability in the Linux kernel dw-edma driver allows attackers to execute code or cause denial of service via improper descriptor termination.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-93042?
CVE-2026-93042 is a high-severity use after free vulnerability in Linux, published on 17 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
dmaengine: dw-edma: Terminate all descriptors without callbacks
The DMA Engine client documentation says in the "Terminate APIs" section of Documentation/driver-api/dmaengine/client.rst:
"No callback functions will be called for any incomplete transfers."
dw-edma instead calls vchan_cookie_complete() when a deferred STOP reaches the interrupt handler. This schedules a callback for the active descriptor and leaves other issued or submitted descriptors queued. A late callback after dmaengine_terminate_sync() can dereference client state that has already been freed, while leftover descriptors may later restart into reused buffers or leak.
Move all issued and submitted descriptors to the terminated list whenever termination completes. For a pending STOP, do this from both the DONE and ABORT paths. Complete their cookies in order without scheduling callbacks.
A STOP can remain pending until the running transfer raises an interrupt. Make device_synchronize() wait for such a pending STOP to complete before releasing terminated descriptors. Reuse it from free_chan_resources(), then release the remaining virt-dma resources. Sleep instead of busy-polling while waiting, and warn if the existing timeout expires.
Which versions are affected by CVE-2026-93042?
How do I fix CVE-2026-93042?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-93042 being exploited?
There is no known exploitation of CVE-2026-93042 in the wild and no public exploit code.
Sources
Also known as AZL-101988, BELL-CVE-2026-93042, DEBIAN-CVE-2026-93042, GHSA-m4jg-4gfw-gm5r, UBUNTU-CVE-2026-93042.