# CVE-2012-0021: Denial of service in n/a

> Remote attackers can crash the Apache HTTP Server daemon by sending a malformed cookie when a threaded MPM is configured.

- **Severity:** Low 2.6 (`AV:N/AC:H/Au:N/C:N/I:N/A:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 28 Jan 2012
- **Updated:** 6 Aug 2024
- **Also known as:** DEBIAN-CVE-2012-0021, GHSA-mq76-p4cp-m2vg

## What is CVE-2012-0021?

CVE-2012-0021 is a low-severity denial of service vulnerability in Apache Http Server, published on 28 Jan 2012. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2012-0021?

It affects 1 product.


Products: Apache Http Server.

## How do I fix CVE-2012-0021?

Upgrade to a fixed version.

## Is CVE-2012-0021 being exploited?

There is no known exploitation of CVE-2012-0021 in the wild and no public exploit code.

## Other vulnerabilities in Apache Http Server

- [CVE-2021-42013](https://insights.sbomify.com/CVE-2021-42013/): Apache HTTP Server Path Traversal (critical 9.8, exploited in the wild)
- [CVE-2024-38475](https://insights.sbomify.com/CVE-2024-38475/): Apache HTTP Server Improper Escaping of Output (critical 9.1, exploited in the wild)
- [CVE-2021-40438](https://insights.sbomify.com/CVE-2021-40438/): Apache HTTP Server-Side Request Forgery (SSRF) (critical 9.0, exploited in the wild)
- [CVE-2019-0211](https://insights.sbomify.com/CVE-2019-0211/): Apache HTTP Server Privilege Escalation (high 7.8, exploited in the wild)
- [CVE-2021-41773](https://insights.sbomify.com/CVE-2021-41773/): Apache HTTP Server Path Traversal (high 7.5, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2012-0021 and fix it if it is affected.

What it is: CVE-2012-0021 is a low-severity denial of service vulnerability in Apache Http Server, published on 28 Jan 2012. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2012-0021 in the wild and no public exploit code.

Affected product: Apache Http Server. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2012-0021/ (Markdown: https://insights.sbomify.com/CVE-2012-0021/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2012-0021
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2012-0021
- OSV: https://osv.dev/vulnerability/CVE-2012-0021

---
From sbomify Insights: https://insights.sbomify.com/CVE-2012-0021/
Summaries are generated and may contain mistakes; the official description above is the record.