CVE-2001-1556

What it is

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.

At a glance

Exploitability

Can be exploited over the network without logging in. Limited direct impact.

Exploit odds

3.6% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2001-12-31 05:00 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-16 21:56 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 3.6% in the next 30 days (EPSS).
• Severity: 5.0 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2001-12-31 05:00 UTC

Last modified

2026-06-16 21:56 UTC

Exploit probability

3.6% · EPSS, next 30 days

Weakness

CWE-532 · Secrets in logs

Record status

Modified

Affected

• Apache Http Server < 1.3.31
• Apache Http Server < 2.0.49

Attack profile CVSS 2.0 · 5.0

Attack vector

Network

Complexity

Low

Authentication

None

Confidentiality

None

Integrity

Partial

Availability

None

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2001-1556.md and follow it. Check whether this project is affected by CVE-2001-1556. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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