What’s Vulnerable › Vulnerabilities

CVE-2026-58049: FFmpeg - Out-of-Bounds Write in RASC Decoder decode_dlta()

• Severity: high (CVSS 8.6 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-06-28 · updated 2026-09-01
• Weakness: CWE-787

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.

Affected products

• FFmpeg: all versions

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-decode-dlta
• 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/errata/RHSA-2026:60520
• https://access.redhat.com/errata/RHSA-2026:61627
• https://access.redhat.com/errata/RHSA-2026:61628
• https://access.redhat.com/errata/RHSA-2026:61629
• https://access.redhat.com/security/cve/CVE-2026-58049

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