CVE-2017-18247
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 · uneditedThe av_audio_fifo_size function in libavutil/audio_fifo.c in Libav 12.2 allows remote attackers to cause a denial of service (NULL pointer dereference) via a crafted media file.
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 · high confidenceA NULL pointer dereference vulnerability exists in the av_audio_fifo_size function within libavutil/audio_fifo.c in Libav 12.2. When processing a specially crafted media file, the function fails to properly validate a pointer before dereferencing it, causing the application to crash and resulting in 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= 12.2CVSS 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
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/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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Identify if Libav is installedRun 'avconv -version' or 'ffmpeg -version' (note: Libav is a fork of FFmpeg and may report as ffmpeg) to determine if Libav utilities are present on the systemAffected if Libav utilities are found on the system
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Determine the exact Libav versionExecute the version command from the previous step and locate the reported version number (for Libav, typically displayed as 'Libav X.Y' or similar)Affected if The reported version is exactly 12.2
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Locate the libavutil library fileSearch for libavutil shared library files (e.g., libavutil.so.* in Linux, avutil*.dll on Windows, or libavutil.*.dylib on macOS) using 'find /usr -name "libavutil*" 2>/dev/null' or equivalent system searchAffected if The libavutil library file exists and is version 12.2
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Verify the vulnerable function existsCheck if the audio_fifo functionality is available by examining the libavutil library or running 'avconv -formats | grep -i fifo' to see if audio fifo support is compiled inAffected if Audio fifo support is present in the installed Libav build
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Confirm processing of untrusted media files is possibleDetermine if the system processes media files from untrusted sources using Libav utilities (check cron jobs, web applications, or media processing pipelines that invoke avconv)Affected if Libav is used to process media files from external or untrusted sources
You are affected only if Libav version 12.2 is installed and is used to process media files from external or untrusted sources, as the NULL pointer dereference triggers when processing a specially crafted media file.
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 dataUpdate Libav to a patched version that includes proper NULL pointer validation in av_audio_fifo_size, or apply a code fix that checks pointer validity before dereferencing.
- Consultation1.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,664.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2017-18247 — 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-2017-18247 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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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
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