CVE-2026-58049

Description

FFmpeg's RASC video decoder (decode_dlta in libavcodec/rasc.c) performs 32-bit reads and writes at the row cursor before the NEXT_LINE row-boundary check and validates the DLTA region in pixel rather than byte units, so a DLTA run on a PAL8 frame can access several bytes past the row allocation. A crafted media stream using the RASC FourCC, decoded by libavcodec, triggers a bitstream-controlled out-of-bounds heap write and adjacent out-of-bounds read, leading to memory corruption.

References

• https://github.com/FFmpeg/FFmpeg/blob/master/libavcodec/rasc.c
• https://github.com/bikini/exploitarium/tree/main/ffmpeg-rasc-dlta-calc-poc
• https://www.vulncheck.com/advisories/ffmpeg-out-of-bounds-write-in-rasc-decoder-decode-dlta