A use-after-free vulnerability was found in FFmpegs RASC video decoder. The decode_move() function initializes a read pointer into a decompressed buffer, but a subsequent reallocation of that same buffer during move-table processing leaves the pointer dangling. An attacker could exploit this by providing a specially crafted AVI file containing a malicious RASC video stream. When a user opens or plays the file, the decoder reads from freed heap memory, which could lead to a denial of service (crash).
Weakness
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.
Potential Mitigations
References
- https://access.redhat.com/security/cve/CVE-2026-12706
- https://bugzilla.redhat.com/show_bug.cgi?id=2490710
- https://lists.ffmpeg.org/archives/list/ffmpeg-devel@ffmpeg.org/message/TTRIJZA7UL6KJTEDMMBGZPLLJERJ3EFX/
- https://patchwork.ffmpeg.org/project/ffmpeg/patch/177766314111.63.10674887811034989327@29965ddac10e/