CVE-2012-0021

What it is

The log_cookie function in mod_log_config.c in the mod_log_config module in the Apache HTTP Server 2.2.17 through 2.2.21, when a threaded MPM is used, does not properly handle a %{}C format string, which allows remote attackers to cause a denial of service (daemon crash) via a cookie that lacks both a name and a value.

At a glance

Exploitability

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

Exploit odds

30.3% chance of exploitation in the next 30 days (EPSS). Higher than most.

Fix

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

Timeline

1. 2012-01-28 04:05 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-16 23:36 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 30.3% in the next 30 days (EPSS).
• Severity: 2.6 LOW (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2012-01-28 04:05 UTC

Last modified

2026-06-16 23:36 UTC

Exploit probability

30.3% · EPSS, next 30 days

Weakness

CWE-20 · Improper input validation

Record status

Modified

Affected

• Apache Http Server 2.2.17
• Apache Http Server 2.2.18
• Apache Http Server 2.2.19
• Apache Http Server 2.2.20
• Apache Http Server 2.2.21

Attack profile CVSS 2.0 · 2.6

Attack vector

Network

Complexity

High

Authentication

None

Confidentiality

None

Integrity

None

Availability

Partial

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-2012-0021.md and follow it. Check whether this project is affected by CVE-2012-0021. 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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