CVE-2004-2264
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 · uneditedFormat string bug in the open_altfile function in filename.c for GNU less 382, 381, and 358 might allow local users to cause a denial of service or possibly execute arbitrary code via format strings in the LESSOPEN environment variable. NOTE: since less is not setuid or setgid, then this is not a vulnerability unless there are plausible scenarios under which privilege boundaries could be crossed
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 confidenceFormat string vulnerability in GNU less (versions 382, 381, 358) in the open_altfile function in filename.c allows local users to execute arbitrary code or cause denial of service via malicious format string specifiers in the LESSOPEN environment variable. Since less is not setuid/setgid, practical exploitation requires specific privilege escalation scenarios.
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= 358= 381= 382CVSS 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
- Partial
AV:N/AC:L/Au:N/C:N/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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Check installed less versionRun 'less --version' or 'less -V' to display the version number of the installed less binaryAffected if The version displayed is exactly 358, 381, or 382
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Verify LESSOPEN environment variable is setRun 'echo $LESSOPEN' in the shell to see if the LESSOPEN environment variable contains a valueAffected if LESSOPEN is set to any value (indicating less will attempt to process this file for opening)
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Confirm LESSOPEN is actively used by lessCheck if the LESSOPEN variable points to a valid script or command by running 'ls -l $(echo $LESSOPEN | cut -d' ' -f1)' to verify the path existsAffected if LESSOPEN points to a valid executable path and will be invoked by less when opening files
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Check for untrusted LESSOPEN input scenariosReview if less is run in contexts where LESSOPEN could be set by untrusted sources, such as in scripts, automated tools, or multi-user environmentsAffected if LESSOPEN can be influenced or set by untrusted users or processes in your environment
You are affected only if your installed less version is exactly 358, 381, or 382 AND the LESSOPEN environment variable is set and will be used when less opens files.
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 GNU less that addresses the format string vulnerability; avoid using LESSOPEN with untrusted input or disable LESSOPEN if not needed.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,800.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2004-2264 — 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-2004-2264 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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