CVE-2003-0844
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 · uneditedmod_gzip 1.3.26.1a and earlier, and possibly later official versions, when running in debug mode without the Apache log, allows local users to overwrite arbitrary files via (1) a symlink attack on predictable temporary filenames on Unix systems, or (2) an NTFS hard link on Windows systems when the "Strengthen default permissions of internal system objects" policy is not enabled.
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 confidencemod_gzip 1.3.26.1a and earlier creates temporary files with predictable filenames when running in debug mode without Apache logging configured. On Unix systems, local users can exploit this via symlink attacks to overwrite arbitrary files. On Windows systems, NTFS hard link attacks are possible when the 'Strengthen default permissions of internal system objects' security policy is disabled.
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<= 1.3.26.1aCVSS 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
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
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 mod_gzip versionLocate the mod_gzip module file (typically named mod_gzip.so or similar) and check its version information, or query Apache's loaded modules for mod_gzip version detailsAffected if The installed version is 1.3.26.1a or any earlier version
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Verify debug mode is disabledInspect the mod_gzip configuration files (httpd.conf, apache.conf, or included configuration files) for any 'mod_gzip_debug' or 'Debug' directives that enable debug modeAffected if Debug mode is enabled in the mod_gzip configuration
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Confirm Apache logging is configuredCheck Apache configuration for active LogFormat and CustomLog directives, or verify that logging is not explicitly disabledAffected if Apache logging is not configured or explicitly disabled
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Check for predictable temporary filesIf debug mode is enabled, examine the Apache temporary directory (typically /tmp or the server's temp folder) for mod_gzip debug log files with predictable namesAffected if Temporary debug files with predictable filenames exist in an accessible directory
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On Windows: verify security policyOn Windows systems, check the 'Strengthen default permissions of internal system objects' security policy setting under Computer Configuration > Windows Settings > Security Settings > Local Policies > Security OptionsAffected if The security policy is disabled and Apache has write access to NTFS volumes
A system is affected if mod_gzip version 1.3.26.1a or earlier is installed with debug mode enabled and without Apache logging configured, creating exploitable temporary 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 dataDisable debug mode in production environments, ensure Apache logging is properly configured, and on Windows systems enable the 'Strengthen default permissions of internal system objects' policy. Apply proper file permissions to prevent symlink/hardlink attacks.
- Consultation3.0 h
- Implementation4.0 h
- Testing2.0 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 $2,880.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2003-0844 — 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-2003-0844 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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