CVE-2023-32570

What it actually does

Race condition in thread_task.c allows concurrent access during dav1d_decode_frame_exit, resulting in memory corruption that terminates the decoding process.

Why it matters to the business

Applications relying on dav1d for AV1 video playback or processing can experience sudden crashes, interrupting video services and requiring restarts or failover handling.

How an attack unfolds

An attacker crafts a malicious AV1 video stream or file that triggers concurrent frame decoding operations; when the race window is hit, the decoder exits abnormally and the hosting application terminates.

How to fix it

Upgrade dav1d to version 1.2.0 or later. On Debian 12 apply package version 6.1.37-1 or newer; on Debian 13 apply 6.3.7-1 or newer. Rebuild and redeploy any statically linked applications after the library update.

How to confirm the fix worked

Confirm the installed dav1d library reports version 1.2.0 or greater, re-run any available regression tests that exercise multi-threaded decoding, and monitor for absence of crashes on previously triggering inputs.

Typical attack path

1. Identify a target application or service that uses dav1d for AV1 decoding
2. Prepare and deliver a specially constructed AV1 bitstream via network, file upload, or media playback
3. Trigger simultaneous decode paths that exercise the thread_task race condition
4. Cause the decoder to invoke dav1d_decode_frame_exit under contention, resulting in a crash

How to detect it

Review application and system logs for segmentation faults or abnormal exits in processes linked against libdav1d, correlate with media file ingestion timestamps, and inspect core dumps or stack traces that reference thread_task.c or dav1d_decode_frame_exit.

What your security team should do

• Prioritize patching Debian systems using the listed fixed package versions within standard maintenance windows
• Scan build pipelines and container images for embedded dav1d versions below 1.2.0
• Add dav1d version checks to software bill-of-materials and dependency monitoring tools