CVE-2002-0364
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 · uneditedBuffer overflow in the chunked encoding transfer mechanism in IIS 4.0 and 5.0 allows attackers to execute arbitrary code via the processing of HTR request sessions, aka "Heap Overrun in HTR Chunked Encoding Could Enable Web Server Compromise."
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 confidenceHeap-based buffer overflow vulnerability in IIS 4.0 and 5.0's chunked encoding transfer mechanism when processing HTR (HTML Application) request sessions. The vulnerability allows remote attackers to execute arbitrary code by sending specially crafted chunked encoding data that overruns heap memory 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= 4.0= 5.0CVSS 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
- Authentication
- None
- Confidentiality
- Partial
- Integrity
- Partial
- Availability
- Partial
AV:N/AC:L/Au:N/C:P/I:P/A:P
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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Identify IIS versionOpen Command Prompt and run: iisreset /status or check the IIS Metabase via adsutil.vbs (in \inetpub\adminscripts) with command: cscript adsutil.vbs get w3svc/ServerVersionAffected if Version equals 4.0 or 5.0 indicates the affected product versions
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Verify HTR ISAPI extension is loadedCheck the IIS Metabase for HTR script mapping. Run: cscript adsutil.vbs get w3svc/ScriptMap '.htr' or examine the IIS Manager under 'Home Directory > Configuration > App Mappings' for a .htr entry pointing to asp.dll or htr.dllAffected if A .htr script mapping exists and points to an ISAPI handler - this enables the vulnerable HTR processing path
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Confirm HTR functionality is accessibleAttempt to access a known HTR file endpoint or verify the HTR extension is not blocked. Check via: cscript adsutil.vbs get w3svc/1/Root/HtrEnabled (returns TRUE if HTR requests allowed)Affected if HTR processing is enabled (returns true) - the server will process .htr requests and trigger the chunked encoding vulnerability path
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Check if chunked transfer encoding is acceptedVerify the server accepts chunked transfer encoding by reviewing IIS request filtering settings or HTTP headers accepted. Default IIS 4.0/5.0 configurations accept chunked encoding.Affected if Chunked transfer encoding is enabled (default behavior) - combined with HTR enabled, this creates the exploit condition
The environment is affected if running IIS 4.0 or IIS 5.0 with HTR scripting enabled and chunked transfer encoding accepted - all three conditions must be present for the vulnerability to be exploitable.
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 dataApply Microsoft security patch for this vulnerability, or upgrade from legacy IIS 4.0/5.0 to a supported IIS version; consider disabling HTR scripting if not required by applications.
- Consultation2.0 h
- Implementation3.0 h
- Testing2.0 h
- Review / QA1.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2002-0364 — 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-2002-0364 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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