---
id: "CVE-2026-125190"
page: "https://infrastack.ai/live/CVE-2026-125190"
kind: "vulnerability"
aliases: ["CVE-2026-125190"]
title: "FFmpeg: crafted MVC2 video leaks process stack memory into frames"
severity: "medium"
cvss: 4.8
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["ffmpeg", "libavcodec", "media-processing", "package", "self-hosted"]
not_affected_if: ["no-mvc2-decoding", "trusted-input-only"]
published_at: "2026-11-09T19:16:54+00:00"
first_seen_at: "2026-11-09T19:28:17+00:00"
updated_at: "2026-11-09T19:32:18+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-125190", "first_seen_at": "2026-11-09T19:28:17+00:00"}]
exploit_sources: []
---

# FFmpeg: crafted MVC2 video leaks process stack memory into frames

Link for people: https://infrastack.ai/live/CVE-2026-125190 (this .md is for agents)

FFmpeg through 9.0.2 has an out-of-bounds palette read in its MVC2 decoder in libavcodec/mvcdec.c. A crafted MVC2 stream can copy uninitialized stack memory into decoded RGB frames, which can expose process memory contents.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Run `ffmpeg -version` and compare the version against the fixed release in the sources, which is unknown here.
- Check whether your services decode untrusted MVC2 input, which the sources do not otherwise detail.

## Timeline

- 2026-11-09T19:28:17+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-125190

## Documents

- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-uninitialized-stack-memory-disclosure-via-mvc2-decoder
- [fix] Patch: github.com https://github.com/FFmpeg/FFmpeg/commit/3a5eb948e76dc6390e4b3cff7becf84bc492b7af

## From the sources

FFmpeg through 9.0.2 contains an information disclosure vulnerability in decode_mvc2() in libavcodec/mvcdec.c that leaks uninitialized stack memory through unchecked palette indices. Attackers can supply a crafted MVC2 stream declaring few colors but referencing higher palette indices, copying process stack contents into decoded RGB frames.

---

_Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai_