FFmpeg Heap Buffer Overflow via RIST Protocol Reader (CVE-2026-75143) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-75143

FFmpeg Heap Buffer Overflow via RIST Protocol Reader

Answer in brief

CVE-2026-75143 records a Unknown severity vulnerability in FFmpeg Heap Buffer Overflow via RIST Protocol Reader. 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 <1c10bcc2e17255dacb717a25ab3db142ce390602	1c10bcc2e17255dacb717a25ab3db142ce390602

Recommended response

Check inventory. Check lockfiles and deployed manifests for FFmpeg/FFmpeg.
Review the reported fix. Update FFmpeg/FFmpeg to 1c10bcc2e17255dacb717a25ab3db142ce390602 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 1c10bcc contains a heap buffer overflow in the RIST protocol reader (libavformat/librist.c). librist_read() ignored its size argument and copied the full received payload length into the caller-provided destination buffer, overflowing it when the payload exceeds the destination size. This is reachable via the async:rist:// URL scheme, where the async wrapper supplies a smaller buffer than the received payload. A remote RIST sender can trigger the overflow by sending a packet whose payload exceeds the caller buffer size.

Quoted source text, attributed separately from HOL analysis.