FFmpeg Integer Narrowing Conversion OOB Memory Access in AV1 RTP Packetizer (CVE-2026-75145) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-75145

FFmpeg Integer Narrowing Conversion OOB Memory Access in AV1 RTP Packetizer

Answer in brief

CVE-2026-75145 records a Unknown severity vulnerability in FFmpeg Integer Narrowing Conversion OOB Memory Access in AV1 RTP Packetizer. The current sources do not mark it as known exploited. The current feed maps FFmpeg/FFmpeg (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 19, 2026Updated Aug 19, 2026Source checked Aug 19, 2026First seen by HOL Aug 19, 2026Material review Aug 19, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps FFmpeg/FFmpeg (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
FFmpeg/FFmpeggeneric	>=0 <b4c199c5906ff53368926c2a5839881f41957e7f	b4c199c5906ff53368926c2a5839881f41957e7f

Recommended response

Check inventory. Check lockfiles and deployed manifests for FFmpeg/FFmpeg.
Review the reported fix. Update FFmpeg/FFmpeg to b4c199c5906ff53368926c2a5839881f41957e7f if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Aug 19, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 19, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 19, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.