libavcodec/pthread_frame.c in FFmpeg before 5.1.2, as used in VLC and other products, leaves stale hwaccel state in worker threads, which allows attackers to trigger a use-after-free and execute arbitrary code in some circumstances (e.g., hardware re-initialization upon a mid-video SPS change when Direct3D11 is used).
https://wrv.github.io/h26forge.pdf
https://security.gentoo.org/glsa/202312-14
https://news.ycombinator.com/item?id=35356201
https://git.ffmpeg.org/gitweb/ffmpeg.git/commit/cc867f2c09d2b69cee8a0eccd62aff002cbbfe11