CVE-2007-6737
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 · uneditedFTPServer.py in pyftpdlib before 0.2.0 does not increment the attempted_logins count for a USER command that specifies an invalid username, which makes it easier for remote attackers to obtain access via a brute-force attack.
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 confidenceIn pyftpdlib before version 0.0.0, the FTP server fails to increment the attempted_logins counter when a USER command provides an invalid username. This allows attackers to perform unlimited brute-force attempts on usernames without triggering any account lockout or rate-limiting mechanisms, since the failed login counter only increments for valid usernames with invalid passwords.
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<= 0.1.1= 0.1CVSS 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 pyftpdlib versionRun 'pip show pyftpdlib' or 'python -c "import pyftpdlib; print(pyftpdlib.__version__)"' to retrieve the installed versionAffected if The installed version is 0.1.1 or earlier, or shows version 0.1.x
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Check FTP server login handling codeInspect the source code of the FTP handler, specifically the handle_user method or login-related functions, for the attempted_logins counter logicAffected if The code shows that attempted_logins only increments for valid usernames (when password verification occurs), not for invalid usernames
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Review login failure tracking configurationExamine if the FTP server has any login attempt tracking, brute-force protection, or account lockout mechanisms configured and enabledAffected if The server relies on attempted_logins counting to trigger lockout or rate-limiting, and this counting skips invalid usernames
You are affected if you are running pyftpdlib version 0.1.1 or earlier and rely on the built-in login attempt counter for brute-force protection, since invalid usernames will not trigger any account lockout or rate limits.
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 pyftpdlib to version 0.2.0 or later where the login attempt counting was fixed to properly track invalid usernames.
- Consultation2.0 h
- Implementation2.0 h
- Testing4.0 h
- Review / QA1.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2007-6737 — 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-2007-6737 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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- Version or environment caveats, and links to real fixes
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