CVE-2017-18242
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 apply_dependent_coupling function in libavcodec/aacdec.c in Libav 12.2 allows remote attackers to cause a denial of service (out-of-bounds read) via a crafted aac 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 confidenceAn out-of-bounds read vulnerability exists in the apply_dependent_coupling function within libavcodec/aacdec.c in Libav 12.2. The vulnerability occurs when processing crafted AAC audio files that trigger improper bounds checking during dependent coupling processing, potentially allowing remote attackers to cause a denial of service by reading memory outside allocated buffers.
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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Check if Libav is installedRun 'avconv -version' or 'avprobe -version' to display the installed Libav versionAffected if The command returns a version string showing Libav 12.2
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Verify the exact Libav version numberParse the version output from the previous step to confirm the version is exactly 12.2Affected if The version is shown as 12.2 - any other version is not affected by this specific CVE
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Confirm the vulnerable library file existsLocate libavcodec/aacdec.c in the Libav source tree or installed library path (typically in /usr/lib/ or compiled from source)Affected if The file exists and corresponds to Libav 12.2 source code containing the apply_dependent_coupling function
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Check if AAC decoding is in useMonitor or review logs/configurations showing Libav processing AAC audio files (using 'ffprobe' or 'avprobe' on audio files, or checking media processing pipelines)Affected if Libav is actively decoding AAC audio files using the vulnerable aacdec module
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Inspect the apply_dependent_coupling functionReview the source code of libavcodec/aacdec.c around the apply_dependent_coupling function for missing bounds checks on coupling channel dataAffected if The code lacks proper bounds validation before accessing dependent coupling channel indices
A user is affected only if they have Libav version 12.2 installed AND are processing AAC audio files that trigger the apply_dependent_coupling function in the vulnerable code path.
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 version that includes the fix for this vulnerability, or apply a patch that adds proper bounds checking in the apply_dependent_coupling function before processing AAC coupling data.
- Consultation3.0 h
- Implementation6.0 h
- Testing4.0 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 $4,224.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2017-18242 — 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-2017-18242 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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