CVE-2009-0084
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 · uneditedUse-after-free vulnerability in DirectShow in Microsoft DirectX 8.1 and 9.0 allows remote attackers to execute arbitrary code via an MJPEG file or video stream with a malformed Huffman table, which triggers an exception that frees heap memory that is later accessed, aka "MJPEG Decompression Vulnerability."
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 confidenceUse-after-free vulnerability in DirectShow's MJPEG decompression where a malformed Huffman table triggers an exception that frees heap memory which is subsequently accessed, allowing remote arbitrary code execution.
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= 8.1= 9.0= 9.0a= 9.0b= 9.0cCVSS 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
- M
- Authentication
- None
- Confidentiality
- Complete
- Integrity
- Complete
- Availability
- Complete
AV:N/AC:M/Au:N/C:C/I:C/A:C
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 DirectX versionRun 'dxdiag' from the command line or check the DirectX version through the system information panel. Look for the DirectX version number displayed.Affected if The installed DirectX version is 8.1, 9.0, 9.0a, 9.0b, or 9.0c
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Verify MJPEG decompression supportCheck if the MJPEG decoder (ijl15.dll, mjpegdec.ax, or similar DirectShow MJPEG splitter/decoder components) is present on the system. These are typically located in the Windows system directory or DirectX installation path.Affected if The MJPEG decompression DirectShow filter is installed and available on the system
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Confirm DirectShow component availabilityVerify that DirectShow is enabled by checking if the DirectShow core files ( quartz.dll or similar DirectShow runtime files) exist and are loaded. This can be done through system information or by inspecting the Windows system directory for DirectShow components.Affected if DirectShow is present and functional on the system with the vulnerable MJPEG component available
The system is affected if it runs any of the DirectX versions 8.1, 9.0, 9.0a, 9.0b, or 9.0c with DirectShow and MJPEG decompression support enabled.
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 · scopedApply Microsoft security updates addressing this vulnerability in DirectX 8.1/9.0, or migrate to Windows versions that include the patched components.
- Apply Microsoft Security Bulletin MS09-011, which addresses the MJPEG Decompression Vulnerability (CVE-2009-0084). This bulletin was released March 2009.
- Download and install the security update from Microsoft Update or the Microsoft Download Center.
- Ensure the update is applied to all systems running the affected DirectX versions (8.1, 9.0, 9.0a, 9.0b).
- After applying the patch, verify the update was successfully installed by checking the installed updates via Control Panel > Programs and Features > View installed updates.
- Restart the system if prompted to complete the installation.
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation4.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2009-0084 — 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-2009-0084 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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A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- 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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