FFmpeg before commit b4c199c contains an incorrect integer narrowing conversion in the AV1 RTP packetizer (libavformat/rtpenc_av1.c). The OBU size is cast to long before comparison against the remaining frame size. On targets where long is 32 bits, including 64-bit Windows, sufficiently large OBU size values are sign-flipped by the narrowing cast, producing a negative value that passes the payload size check. This allows an oversized OBU to bypass the safety bound on affected platforms, leading to out-of-bounds memory access when the oversized value is subsequently used as a copy length.
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Fixes

Solution

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Workaround

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History

Fri, 21 Aug 2026 20:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Wed, 19 Aug 2026 19:15:00 +0000

Type Values Removed Values Added
First Time appeared Ffmpeg
Ffmpeg ffmpeg
Vendors & Products Ffmpeg
Ffmpeg ffmpeg

Wed, 19 Aug 2026 16:45:00 +0000

Type Values Removed Values Added
Description FFmpeg before commit b4c199c contains an incorrect integer narrowing conversion in the AV1 RTP packetizer (libavformat/rtpenc_av1.c). The OBU size is cast to long before comparison against the remaining frame size. On targets where long is 32 bits, including 64-bit Windows, sufficiently large OBU size values are sign-flipped by the narrowing cast, producing a negative value that passes the payload size check. This allows an oversized OBU to bypass the safety bound on affected platforms, leading to out-of-bounds memory access when the oversized value is subsequently used as a copy length.
Title FFmpeg Integer Narrowing Conversion OOB Memory Access in AV1 RTP Packetizer
Weaknesses CWE-681
References
Metrics cvssV3_1

{'score': 5.8, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:H'}

cvssV4_0

{'score': 5.8, 'vector': 'CVSS:4.0/AV:L/AC:H/AT:N/PR:N/UI:P/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-08-21T19:52:12.755Z

Reserved: 2026-08-17T18:39:57.662Z

Link: CVE-2026-75145

cve-icon Vulnrichment

Updated: 2026-08-21T19:52:07.912Z

cve-icon NVD

Status : Received

Published: 2026-08-19T17:21:12.863

Modified: 2026-08-21T20:16:42.050

Link: CVE-2026-75145

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-20T14:00:04Z

Weaknesses