CVE-2026-58049
Severity CVSS v4.0:
HIGH
Type:
CWE-787
Out-of-bounds Write
Publication date:
28/06/2026
Last modified:
30/06/2026
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.
Impact
Base Score 4.0
8.80
Severity 4.0
HIGH
Base Score 3.x
8.60
Severity 3.x
HIGH
References to Advisories, Solutions, and Tools
- 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
- https://access.redhat.com/security/cve/CVE-2026-58049
- https://bugzilla.redhat.com/show_bug.cgi?id=2493952
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-58049.json