CVE-2026-58049

Summary

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.

Affected Software

Weaknesses

• CWE-787: Out-of-bounds Write

ADP Enrichment

CISA ADP Vulnrichment

• SSVC:
• Exploitation: none
  • Automatable: yes
  • Technical Impact: partial

FFmpeg: FFmpeg: Memory corruption via crafted RASC video stream

Additional References

• 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

References

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

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