CVE-2026-58049 | FFmpeg's RASC video decoder (decode_dlta in libavcodec/rasc.… | CVSS 8.6 HIGH

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.

Metadata

CVE ID: CVE-2026-58049
State: PUBLISHED
Assigner: VulnCheck
Reserved: 2026-06-28 00:55 UTC
Published: 2026-06-28 01:32 UTC
Last updated: 2026-06-28 01:32 UTC
Primary CWE: CWE-787
Out-of-bounds Write
Vendor / Product: FFmpeg / FFmpeg
Sources: cve.org · NVD

Severity & Metrics

8.6 HIGH CVSS 3.1

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

Affected products (1)

Vendor	Product	Platform	Versions
FFmpeg	FFmpeg	—	0 ≤ bcd2c69e087a09b07cf45c6bd2428ee1ccb2925c

Weakness (CWE)

CWE	Source	Description
CWE-787	cna	Out-of-bounds Write

CVSS scores (2)

Score	Severity	Version	Source	Vector
8.8	HIGH	4.0	cna	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N
8.6	HIGH	3.1	cna	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H

References (3)

Proof of Concept https://github.com/bikini/exploitarium/tree/main/ffmpeg-rasc-dlta-calc-poc
libavcodec/rasc.c https://github.com/FFmpeg/FFmpeg/blob/master/libavcodec/rasc.c
VulnCheck Advisory: FFmpeg - Out-of-Bounds Write in RASC Decoder decode_dlta() https://www.vulncheck.com/advisories/ffmpeg-out-of-bounds-write-in-rasc-decoder-decode-dlta