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7.1

mod_gzip can let local user replace any file

CVE-2003-0844 · published 22 years ago
Summary

When mod_gzip runs in debug mode without an Apache log, a user with access to the server can trick it into writing over any file by using a symbolic link on Unix or a hard link on Windows. This could let an attacker modify system or application files and potentially disrupt operations. Disable debug mode or ensure logging is enabled, and apply the latest update or configure strict file‑system permissions to prevent the link attacks.

What to do

The CVE record does not list a fixed version. Check the vendor's site or the advisory links below - a fix may already be released.

Affected software
VendorProductAffected versions
schroepl mod_gzip <= 1.3.26.1a
cpe:2.3:a:schroepl:mod_gzip:*:*:*:*:*:*:*:*
Original advisory text
mod_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 ...
mod_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.
References
Fix within
Internet-facing 60 days
Internal At next upgrade
  • Not known to be exploited
  • Needs hands-on effort to exploit (estimated)
  • Gives an attacker partial control (estimated)
Severity
7.1 High
Exploitation
<1% chance of attack within 30 days
Type
CWE-59Link Following
Timeline
Published17 Nov 2003
Updated4 Nov 2026
First seen29 Sep 2026
Sources
CVE-2003-0844 · NVD
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