Vulnerability 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.
CVSS Score
HIGH
Related Weaknesses (CWE)
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-
- https://access.redhat.com/errata/RHSA-2026:43711
- https://access.redhat.com/errata/RHSA-2026:51180
- https://access.redhat.com/errata/RHSA-2026:52832
- https://access.redhat.com/errata/RHSA-2026:52833
- 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
FAQ
What is CVE-2026-58049?
CVE-2026-58049 is a vulnerability with a CVSS score of 8.6 (HIGH). 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 ...
How severe is CVE-2026-58049?
CVE-2026-58049 has been rated HIGH with a CVSS base score of 8.6/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-58049?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.