CVE-2019-12874
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 · uneditedAn issue was discovered in zlib_decompress_extra in modules/demux/mkv/util.cpp in VideoLAN VLC media player 3.x through 3.0.7. The Matroska demuxer, while parsing a malformed MKV file type, has a double free.
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 double free vulnerability exists in VLC media player's Matroska demuxer (modules/demux/mkv/util.cpp) in the zlib_decompress_extra function. When parsing a malformed MKV file, memory is freed twice, potentially allowing arbitrary code execution or denial of service. The CVSS 9.8 indicates trivial exploitability.
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>= 3.0.0, <= 3.0.7CVSS 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
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/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 if VLC is installedRun 'vlc --version' or 'vlc -V' from command line, or check installed programs list in your systemAffected if VLC is present on the system
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Determine the installed VLC versionExecute 'vlc --version' and locate the version number in the output (e.g., 'VLC media player 3.0.x')Affected if The reported version falls within 3.0.0 through 3.0.7 inclusive
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Verify the Matroska demuxer module existsCheck that VLC supports MKV playback by attempting to open an MKV file or examining VLC's demuxer modules via 'vlc --list' or documentationAffected if MKV demuxer is available and the version range check in step 2 shows vulnerability
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Confirm the zlib_decompress_extra function is presentThis is a code-level check: examine the VLC installation binary or source for modules/demux/mkv/util.cpp containing the zlib_decompress_extra functionAffected if The vulnerable function exists in the installed binary and version is 3.0.0-3.0.7
A user is affected if VLC Media Player version 3.0.0 through 3.0.7 is installed and the Matroska (MKV) demuxer is functional on their system.
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.
dbcve · scopedDo not open untrusted or malformed MKV files in vulnerable VLC versions until upgrading to a patched version (VLC 3.0.8 or later). Users should only play media from trusted sources.
VLC Media Player 3.0.8 or later
- 1. Uninstall the current VLC Media Player version (3.0.0 - 3.0.7) from your system
- 2. Download VLC Media Player version 3.0.8 or later from the official VideoLAN website (https://www.videolan.org/)
- 3. Verify the downloaded installer matches your operating system (Windows, macOS, or Linux)
- 4. Run the installer and follow the prompts to complete the installation
- 5. After installation, verify the installed version by going to Help > About VLC and confirm the version is 3.0.8 or higher
- 6. Avoid opening untrusted or malformed MKV files from untrusted sources
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation1.0 h
- Testing4.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2019-12874 — 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-2019-12874 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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