CVE-2005-2151
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 · uneditedspf.c in Courier Mail Server does not properly handle DNS failures when looking up Sender Policy Framework (SPF) records, which could allow attackers to cause memory corruption.
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 · moderate confidenceThe spf.c component in Courier Mail Server fails to properly handle DNS lookup failures when querying Sender Policy Framework (SPF) records. This improper error handling leads to memory corruption, which could potentially be exploited by remote attackers to cause undefined behavior in the mail server.
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= 0.46= 0.47= 0.48= 0.48.1= 0.48.2= 0.49.0= 0.50.0CVSS 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
- None
- Integrity
- Partial
- Availability
- None
AV:N/AC:L/Au:N/C:N/I:P/A:N
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 Courier Mail Server versionRun 'courier --version' or check the package management system (e.g., 'dpkg -l courier-mta' or 'rpm -qi courier-mta')Affected if The installed version matches 0.46, 0.47, 0.48, 0.48.1, 0.48.2, 0.49.0, or 0.50.0
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Confirm SPF support is enabledLook for SPF-related configuration in Courier configuration files, typically in the esmtpd or esmtp configuration, or check for 'SPF' in the server's runtime settingsAffected if SPF validation is enabled and the server performs SPF lookups for incoming mail
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Verify DNS SPF lookup functionality is activeCheck mail server logs for SPF-related entries during mail reception, or test by sending a test email and observing if SPF checks are performedAffected if The server is actively performing SPF DNS lookups on incoming mail
You are affected if you are running any of the listed versions (0.46 through 0.50.0) AND have SPF validation enabled, as the vulnerability triggers when the server performs SPF DNS lookups that fail.
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 or patch the Courier Mail Server to a version that properly handles DNS failures in SPF lookups. If no patch is available, consider disabling SPF validation as a temporary measure until a fix can be applied.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA4.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2005-2151 — 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-2005-2151 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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