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FfmpegApplication

CVE-2011-3937

HIGH · 10.0 CVSS v2.0 Published 2013-01-05
Fix available
A fix is available. Upgrade to after 0.9.1 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
The H.263 codec (libavcodec/h263dec.c) in FFmpeg 0.7.x before 0.7.12, 0.8.x before 0.8.11, and unspecified versions before 0.10, and in Libav 0.5.x before 0.5.9, 0.6.x before 0.6.6, 0.7.x before 0.7.5, and 0.8.x before 0.8.1 has unspecified impact and attack vectors related to "width/height changing with frame threads."

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

A vulnerability exists in the H.263 video decoder (libavcodec/h263dec.c) in FFmpeg and Libav where improper handling of width/height dimension changes during frame threading can lead to memory corruption. This is a critical-severity flaw (CVSS 10) in the video decoding pipeline that could allow remote code execution when processing specially crafted H.263 streams.

MitigationUpgrade to FFmpeg 0.7.12+, 0.8.11+, 0.10+ or Libav 0.5.9+, 0.6.6+, 0.7.5+, 0.8.1+ to obtain patched versions. Until upgraded, restrict processing of untrusted H.263 video content and disable frame threading if possible.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
FfmpegApplication
Affected:<= 0.9.1= 0.3= 0.3.1= 0.3.2= 0.3.3= 0.3.4= 0.4.0= 0.4.2= 0.4.3= 0.4.4= 0.4.5= 0.4.6
LibavApplication
Affected:= 0.5= 0.5.1= 0.5.2= 0.5.3= 0.5.4= 0.5.5= 0.5.6= 0.5.7= 0.5.8= 0.6= 0.6.1= 0.6.2

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Authentication
None
Confidentiality
Complete
Integrity
Complete
Availability
Complete

AV:N/AC:L/Au:N/C:C/I:C/A:C

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed library version
    Run 'ffmpeg -version' or 'avconv -version' to determine if FFmpeg or Libav is installed and obtain the exact version number
    Affected if The version matches any of the affected versions listed (FFmpeg <= 0.9.1, 0.3.x through 0.4.6; Libav 0.5.x through 0.6.2)
  2. Confirm H.263 decoder is in use
    Inspect any application logs, configurations, or media processing pipelines that decode H.263 video streams using the identified FFmpeg/Libav installation
    Affected if H.263 video content is being processed by the affected library version
  3. Check frame threading configuration
    Examine the decoder or application configuration for frame threading settings; in code, check if avctx->thread_count > 1 or frame threading is explicitly enabled for the H.263 decoder
    Affected if Frame threading (multiple decode threads) is enabled, as the vulnerability requires this condition to trigger the dimension change handling flaw

You are affected if your environment runs a version of FFmpeg (0.3.x to 0.9.1) or Libav (0.5.x to 0.6.2) that processes H.263 video streams with frame threading enabled.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to a release after 0.9.1
Interim mitigation

Upgrade to FFmpeg 0.7.12+, 0.8.11+, 0.10+ or Libav 0.5.9+, 0.6.6+, 0.7.5+, 0.8.1+ to obtain patched versions. Until upgraded, restrict processing of untrusted H.263 video content and disable frame threading if possible.

Recommended fix High confidence

FFmpeg 0.10+ (or 0.7.12+ / 0.8.11+ for specific branches); Libav 0.8.1+ (or 0.5.9+/0.6.6+/0.7.5+ for respective branches)

  1. 1. Identify the current FFmpeg or Libav version installed on the system using: ffmpeg -version or avconv -version
  2. 2. For FFmpeg users: Upgrade to version 0.10.0 or later, or specifically to 0.7.12+ for the 0.7.x branch, or 0.8.11+ for the 0.8.x branch
  3. 3. For Libav users: Upgrade to version 0.8.1 or later for the 0.8.x branch, or 0.5.9+ for the 0.5.x branch, 0.6.6+ for 0.6.x, or 0.7.5+ for 0.7.x
  4. 4. Verify the upgrade was successful by checking: ffmpeg -version or avconv -version
  5. 5. Test critical video processing workflows to ensure functionality remains intact after the upgrade
Caveat Major version upgrades (e.g., 0.9.x to 0.10+) may introduce API changes affecting existing integrations or require recompilation of linked applications

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Ffmpeg Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2011-3937 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data