CVE-2001-1556

Severity: medium (CVSS 5.0 v2.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 3.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2001-12-31 · updated 2026-06-16
Weakness: CWE-532

Description

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; from 2.0.0 before 2.0.49 — fixed in 1.3.31, 2.0.49

How to fix

Upgrade to a fixed version: Apache HTTP Server 1.3.31, 2.0.49. Check the vendor advisory for mitigations.

References

http://archives.neohapsis.com/archives/bugtraq/2001-10/0231.html
http://httpd.apache.org/docs/logs.html
http://www.iss.net/security_center/static/7363.php
http://archives.neohapsis.com/archives/bugtraq/2001-10/0231.html
http://httpd.apache.org/docs/logs.html
http://www.iss.net/security_center/static/7363.php

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