CVE-2017-18246
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 pcm_encode_frame function in libavcodec/pcm.c in Libav 12.2 allows remote attackers to cause a denial of service (heap-based buffer over-read) 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 heap-based buffer over-read vulnerability exists in the pcm_encode_frame function in libavcodec/pcm.c of Libav 12.2. When processing a crafted media file, the function reads beyond the allocated buffer boundaries on the heap, leading to 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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Detect Libav installationRun 'avconv -version' or 'ffmpeg -version' (if avconv is a symlink) to check if Libav is present on the systemAffected if Command fails or returns no output, indicating Libav is not installed
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Identify installed Libav versionExamine the version output from the previous step and record the exact version number displayed (e.g., Libav 12.2)Affected if The version shown is 12.2 exactly
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Check for libavcodec libraryLocate the libavcodec library file on the system using 'find /usr -name "libavcodec*" 2>/dev/null' or check your package managerAffected if libavcodec library exists and is version 12.2
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Verify PCM encoding capability is in useReview application logs or configuration to determine if PCM audio encoding or decoding is being performed using libavcodecAffected if The system processes PCM-encoded media files using Libav's pcm encoder/decoder
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Inspect the vulnerable pcm.c fileIf libavcodec source is present, verify the file libavcodec/pcm.c exists and check its pcm_encode_frame function for proper bounds checkingAffected if The pcm_encode_frame function in libavcodec/pcm.c lacks bounds validation
You are affected only if Libav version 12.2 is installed AND your system processes PCM audio files using the vulnerable pcm_encode_frame function
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 Libav that includes proper bounds checking in the pcm_encode_frame function. Alternatively, implement input validation to reject malformed PCM headers before processing.
- Consultation2.0 h
- Implementation3.0 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 $2,800.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2017-18246 — 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-2017-18246 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
- No weaponised exploit code, or anything meant to cause harm
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