CVE-2017-9871
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 III_i_stereo function in layer3.c in mpglib, as used in libmpgdecoder.a in LAME 3.99.5 and other products, allows remote attackers to cause a denial of service (stack-based buffer overflow and application crash) or possibly have unspecified other impact via a crafted audio 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 · moderate confidenceStack-based buffer overflow in the III_i_stereo function in layer3.c of mpglib (libmpgdecoder.a used by LAME 3.99.5) allows remote attackers to crash applications or potentially achieve code execution via crafted audio files. The vulnerability occurs during stereo audio processing when insufficient bounds checking permits overflow into stack memory.
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= 3.99.5CVSS 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
- Local
- Complexity
- Low
- Privileges
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/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 installed LAME versionRun 'lame --version' or query your package manager for installed lame package versionAffected if Version is exactly 3.99.5
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Locate libmpgdecoder.a librarySearch for libmpgdecoder.a in system library paths (/usr/lib, /usr/local/lib) or within project dependenciesAffected if libmpgdecoder.a exists and is linked to the application
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Identify if application uses mpglib for audio decodingCheck application dependencies using 'ldd' on Linux or examine build configuration for linking against mpglib/mpg123 librariesAffected if Application links against mpglib library from LAME 3.99.5
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Verify stereo audio processing path is in useReview application code or configuration to confirm audio decoding handles stereo (2-channel) MP3 filesAffected if Application decodes stereo audio using the vulnerable mpglib library version 3.99.5
A user is affected if LAME 3.99.5 or a library derived from it (libmpgdecoder.a) is installed and processes stereo audio files.
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 or patch the vulnerable mpglib/library code to add proper bounds validation in the III_i_stereo function; validate audio file input before decoding; consider upgrading to a patched version of LAME if available.
- Consultation2.0 h
- Implementation4.0 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 $3,328.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2017-9871 — 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-2017-9871 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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- Version or environment caveats, and links to real fixes
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