CVE-2001-0721
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 · uneditedUniversal Plug and Play (UPnP) in Windows 98, 98SE, ME, and XP allows remote attackers to cause a denial of service (memory consumption or crash) via a malformed UPnP request.
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 confidenceThe UPnP service in Windows 98, 98SE, ME, and XP fails to properly validate malformed UPnP requests, allowing remote attackers to send specially crafted packets that cause excessive memory consumption or system crash.
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 dataall versionsall versionsall versionsall versionsCVSS 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
- None
- Integrity
- None
- Availability
- Partial
AV:N/AC:L/Au:N/C:N/I:N/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 the Windows versionRun 'winver' or check System Properties to confirm the installed operating systemAffected if If the OS is Windows 98, Windows 98SE, Windows ME, or Windows XP (any version), the system falls within the affected product range
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Locate the UPnP serviceOpen Services control panel and look for 'Universal Plug and Play' service, or run 'sc query upnphost' on XP systemsAffected if If the UPnP service entry exists on the system, it is a candidate for this vulnerability
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Determine UPnP service stateCheck the service status in Services panel or run 'sc query upnphost' to see if it shows STATE: RUNNINGAffected if If the UPnP service is currently running, the vulnerability is active and exploitable
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Verify UPnP network listenerRun 'netstat -an | findstr :1900' or use a port scanner to check if UDP port 1900 is listeningAffected if If UDP port 1900 is open and listening, the system is exposed to network-based exploitation of this flaw
A system is affected if it runs Windows 98, 98SE, ME, or XP AND has the UPnP service installed and running with port 1900/UDP exposed.
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 dataDisable the UPnP service on legacy systems if not required, or block UPnP traffic (port 1900/UDP) at network perimeter firewalls. Consider retiring these unsupported operating systems.
- Consultation2.0 h
- Implementation1.0 h
- Testing2.0 h
- Review / QA1.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2001-0721 — 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-2001-0721 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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