---
id: "CVE-2026-125241"
page: "https://infrastack.ai/live/CVE-2026-125241"
kind: "vulnerability"
aliases: ["CVE-2026-125241"]
title: "FFmpeg: crafted FLIC file overflows heap memory in video decoder"
severity: "high"
cvss: 7.3
epss: null
exploited: false
status: "open"
category: "package"
products: [{"name": "ffmpeg", "fixed": [], "affected": "<= 9.0.2", "ecosystem": "vendor"}]
ecosystems: []
tags: ["ffmpeg", "libavcodec", "media-processing", "package"]
not_affected_if: ["no-untrusted-flic-input"]
published_at: "2026-11-09T19:17:02+00:00"
first_seen_at: "2026-11-09T19:28:20+00:00"
updated_at: "2026-11-09T19:31:37+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-125241", "first_seen_at": "2026-11-09T19:28:20+00:00"}, {"source": "analyst", "url": null, "first_seen_at": "2026-11-09T19:31:37+00:00"}]
exploit_sources: []
---

# FFmpeg: crafted FLIC file overflows heap memory in video decoder

Link for people: https://infrastack.ai/live/CVE-2026-125241 (this .md is for agents)

FFmpeg's FLIC video decoder in libavcodec/flicvideo.c fails to bounds-check pixel writes when frames use a negative stride. A crafted FLIC file can write past frame storage, corrupting heap memory to crash the application or possibly run code.

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

## Affected

- vendor:ffmpeg affected <= 9.0.2 fixed no fixed version listed

## How to check

- Run `ffmpeg -version`; versions up to and including 9.0.2 are in the stated range.
- Find where libavcodec is linked (`ldd`, dependency lists).
- Check whether your tree contains commit 27f612b (`git merge-base --is-ancestor 27f612b306eb04f81138173f705df9a9b055b01d HEAD`).
- Also check if you disabled the flic decoder at build time (`ffmpeg -decoders | grep -i flic`); if absent you are not reached.

## Fix

Fixed upstream in commit 27f612b306eb04f81138173f705df9a9b055b01d (master). No release containing it is named in the sources read; until one ships, build from a tree with that commit or take your distro's backport.

## Timeline

- 2026-11-09T19:28:20+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-125241
- 2026-11-09T19:31:37+00:00 analyst — Read upstream commit 27f612b (flicvideo.c, bounds both ends via pixel_range(); found by Joshua Rogers/AISLE) and VulnCheck advisory. Neither names a fixed release; affected 'through 9.0.2'. Default-build status of FLIC decoder not confirmed from a source. Exa credits exhausted, no social search done.

## Documents

- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-heap-buffer-overflow-via-flic-decoder-check-pixel-ptr
- [fix] Patch: github.com https://github.com/FFmpeg/FFmpeg/commit/27f612b306eb04f81138173f705df9a9b055b01d

## From the sources

FFmpeg through 9.0.2 contains a heap buffer overflow vulnerability in libavcodec/flicvideo.c that allows attackers to write out of bounds because check_pixel_ptr() checks only one bound with negative-stride frames. Attackers can supply a crafted FLIC file whose RLE and delta chunks write pixel data past frame storage, corrupting heap memory to crash applications or possibly execute code.

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