CVE-2000-0091
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 vchkpw/vpopmail POP authentication package allows remote attackers to gain root privileges via a long username or password.
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 confidenceBuffer overflow in the vchkpw/vpopmail POP3 authentication component allows remote attackers to execute arbitrary code with root privileges by sending an excessively long username or password during POP authentication.
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= vchkpw_3.4.1= vchkpw_3.4.2= vchkpw_3.4.3= vchkpw_3.4.4= vchkpw_3.4.5= vchkpw_3.4.6= vchkpw_3.4.7= vchkpw_3.4.8= vchkpw_3.4.9= vchkpw_3.4.11CVSS 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
- Complete
- Integrity
- Complete
- Availability
- Complete
AV:N/AC:L/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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Locate the vchkpw binarySearch for the vchkpw executable on the system using 'find / -name vchkpw -type f 2>/dev/null' or check common paths such as /home/vpopmail/bin/vchkpw, /usr/local/vpopmail/bin/vchkpw, or /var/vpopmail/bin/vchkpwAffected if The vchkpw binary exists on the system, indicating vpopmail is installed
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Identify the installed vchkpw versionRun 'vchkpw -V' or 'vchkpw -v' to display version information. If that fails, use 'strings' on the binary to look for version strings, or check the RPM/package version if installed via package managerAffected if The version matches 3.4.1, 3.4.2, 3.4.3, 3.4.4, 3.4.5, 3.4.6, 3.4.7, 3.4.8, 3.4.9, or 3.4.11
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Verify POP3 service is exposedCheck if POP3 port 110 is listening with 'netstat -tlnp | grep :110' or 'ss -tlnp | grep :110'. Also verify that vchkpw is configured as the POP3 authentication program in /etc/xinetd.d/pop3 or similar inetd configurationAffected if POP3 service is running and using vchkpw for authentication
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Confirm vpopmail is handling POP3 authenticationExamine the POP3 service configuration in /etc/xinetd.d/, /etc/inetd.conf, or the mail server configuration (such as qmail-popup or similar) to verify vchkpw is set as the authentication binaryAffected if vchkpw is configured as the POP3 authentication handler
If the vchkpw binary exists and its version is one of 3.4.1 through 3.4.9 or 3.4.11, and POP3 service is exposed using vchkpw for authentication, the system is affected by this vulnerability.
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 dataUpgrade to a patched version of vpopmail or migrate to a modern, maintained mail authentication solution; if vpopmail must remain in use temporarily, restrict network access to the POP service.
- Consultation3.0 h
- Implementation12.0 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 $5,952.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2000-0091 — 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-2000-0091 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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