CVE-2001-1556: Apache HTTP Server

Medium severity, CVSS 5.0. EPSS: 3.6% chance of exploitation in the next 30 days.

The log files in Apache web server contain information directly supplied by clients and does not filter or quote control characters, which could allow remote attackers to hide HTTP requests and spoof source IP addresses when logs are viewed with UNIX programs such as cat, tail, and grep.

Affected products

• Apache HTTP Server: from 1.3.0, before 1.3.31 (fixed in 1.3.31); from 2.0.0, before 2.0.49 (fixed in 2.0.49)

Published 2001-12-31. Last modified 2026-06-16.