FFmpeg before commit 65b0dab contains an out-of-bounds read in the DASH demuxer (libavformat/dashdec.c). When a live DASH manifest is refreshed with a startNumber that is lower than the previous value, the current sequence number is driven negative. The fragment retrieval function checked only the upper bound before indexing the fragments array, allowing a negative index to be used and causing an out-of-bounds read. A malicious or misconfigured DASH server can trigger this by serving a live manifest with a decreasing startNumber across a manifest refresh.
Advisories

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Fixes

Solution

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Workaround

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History

Fri, 28 Aug 2026 12:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Important


Thu, 20 Aug 2026 15:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

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


Wed, 19 Aug 2026 18:15:00 +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 65b0dab contains an out-of-bounds read in the DASH demuxer (libavformat/dashdec.c). When a live DASH manifest is refreshed with a startNumber that is lower than the previous value, the current sequence number is driven negative. The fragment retrieval function checked only the upper bound before indexing the fragments array, allowing a negative index to be used and causing an out-of-bounds read. A malicious or misconfigured DASH server can trigger this by serving a live manifest with a decreasing startNumber across a manifest refresh.
Title FFmpeg Out-of-Bounds Read in DASH Demuxer via dashdec.c
Weaknesses CWE-125
References
Metrics cvssV3_1

{'score': 8.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H'}

cvssV4_0

{'score': 7.2, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:H/SC:N/SI:N/SA:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-08-20T14:56:11.985Z

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

Link: CVE-2026-75146

cve-icon Vulnrichment

Updated: 2026-08-20T14:56:02.474Z

cve-icon NVD

Status : Received

Published: 2026-08-19T17:21:13.057

Modified: 2026-08-20T15:18:38.097

Link: CVE-2026-75146

cve-icon Redhat

Severity : Important

Publid Date: 2026-08-19T16:28:19Z

Links: CVE-2026-75146 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-08-20T14:30:03Z

Weaknesses