---
id: "CVE-2026-125184"
page: "https://infrastack.ai/live/CVE-2026-125184"
kind: "vulnerability"
aliases: ["CVE-2026-125184"]
title: "FFmpeg: CamStudio decoder leaks uninitialized heap memory into decoded video"
severity: "medium"
cvss: 4.8
epss: null
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["ffmpeg", "media-processing", "runtime", "self-hosted", "transcoding"]
not_affected_if: ["ffmpeg-outside-6.1-9.0.2", "no-untrusted-avi-input"]
published_at: "2026-11-09T19:16:53+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-2026-125184", "first_seen_at": "2026-11-09T19:28:17+00:00"}]
exploit_sources: []
---

# FFmpeg: CamStudio decoder leaks uninitialized heap memory into decoded video

Link for people: https://infrastack.ai/live/CVE-2026-125184 (this .md is for agents)

FFmpeg's CamStudio (CSCD) decoder copies uninitialized heap memory into decoded frames when a compressed payload decompresses to fewer bytes than the frame size. An attacker who supplies a crafted AVI file can recover heap contents from the decoded or re-encoded output.

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

## How to check

- Check the installed FFmpeg version with `ffmpeg -version`; affected releases are `6.1` through `9.0.2`.
- Check whether your application decodes untrusted AVI files using the CamStudio codec (CSCD).

## Fix

- Move to a FFmpeg release newer than `9.0.2`; the sources do not name the exact fixed version.

## Timeline

- 2026-11-09T19:28:17+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-125184

## Documents

- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/ffmpeg-6.1-through-9.0.2-information-disclosure-via-camstudio-decoder-cscd-c
- [fix] Patch: github.com https://github.com/FFmpeg/FFmpeg/commit/e58c4eb98f0f3c0523089fb9d037eedfcbd204d9

## From the sources

FFmpeg 6.1 through 9.0.2 contains an information disclosure vulnerability in the CamStudio decoder (libavcodec/cscd.c) that copies uninitialized heap memory into decoded frames when decompressed payloads are short. Attackers can supply a crafted AVI with a CSCD stream whose LZO or zlib frames decompress to fewer bytes than the frame size, recovering heap contents from the decoded or re-encoded output.

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