CVE-2020-20448
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 · uneditedFFmpeg 4.1.3 is affected by a Divide By Zero issue via libavcodec/ratecontrol.c, which allows a remote malicious user to cause a Denial of Service.
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 confidenceFFmpeg 4.1.3 contains a divide-by-zero vulnerability in libavcodec/ratecontrol.c within the rate control logic. A remote attacker can trigger this by providing a specially crafted input that causes the division operation to receive a zero divisor, resulting in a crash and denial of service.
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= 4.1.3CVSS 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
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
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 checksWork through these to decide whether this CVE applies to you.
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Determine installed FFmpeg versionRun `ffmpeg -version` or check via package manager (e.g., `dpkg -l | grep ffmpeg`, `rpm -qa | grep ffmpeg`)Affected if The version displayed is exactly 4.1.3
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Verify FFmpeg binary build includes libavcodecRun `ffmpeg -codecs` or `ffmpeg -encoders` to list available codecs; libavcodec is core to FFmpegAffected if libavcodec is present, which is standard for FFmpeg builds - the vulnerability exists in the ratecontrol.c component of this library
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Confirm whether untrusted or externally-sourced media files are being processedAudit media processing workflows to identify if input files come from untrusted sources, network endpoints, or user uploadsAffected if FFmpeg processes media files from sources you do not fully control or cannot verify as trusted
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Identify if rate control is actively used during encodingCheck encoding commands and scripts for presence of bitrate-related flags (e.g., -b:v, -b:a, -crf, -pass) or rate control parameters; rate control is typically enabled by default in encodingAffected if Encoding operations use bitrate control or CRF settings, which invoke the vulnerable rate control logic in libavcodec/ratecontrol.c
You are affected only if your installed FFmpeg version is exactly 4.1.3 and you use it to process media files, particularly from untrusted sources, with encoding rate control enabled.
Generated from the published advisory. Verify against your own configuration.
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.
From vendor dataUpgrade to a patched version of FFmpeg beyond 4.1.3. If immediate updating is not feasible, implement input validation on media files before processing and apply resource limits to constrain the attack surface.
- Consultation3.0 h
- Implementation6.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,984.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-20448 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2020-20448 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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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.
- 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
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