CVE-2026-58049

HIGH 8.6

FFmpeg - Out-of-Bounds Write in RASC Decoder decode_dlta()

CVSS Score

8.6

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-787
Vendor	ffmpeg
Product	ffmpeg
Published	Jun 28, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

Low

Availability

High

Affected Versions

FFmpeg / FFmpeg

0 ≤ bcd2c69e087a09b07cf45c6bd2428ee1ccb2925c

References

NVD ↗ CVE.org ↗ EPSS Data ↗

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

Credits

ashdfrkl