# CVE-2012-2733: Denial of service in n/a

> Remote attackers can cause denial of service via memory consumption by sending excessive header data to Apache Tomcat's HTTP NIO connector.

- **Severity:** Medium 5.0 (`AV:N/AC:L/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:** 16 Nov 2012
- **Updated:** 6 Aug 2024
- **Also known as:** GHSA-cpr9-82wf-f629

## What is CVE-2012-2733?

CVE-2012-2733 is a medium-severity denial of service vulnerability in Apache Tomcat, published on 16 Nov 2012. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

java/org/apache/coyote/http11/InternalNioInputBuffer.java in the HTTP NIO connector in Apache Tomcat 6.x before 6.0.36 and 7.x before 7.0.28 does not properly restrict the request-header size, which allows remote attackers to cause a denial of service (memory consumption) via a large amount of header data.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2012-2733?

It affects 1 product.


Products: Apache Tomcat.

## How do I fix CVE-2012-2733?

Upgrade to a fixed version.

## Is CVE-2012-2733 being exploited?

There is no known exploitation of CVE-2012-2733 in the wild and no public exploit code.

## Other vulnerabilities in Apache Tomcat

- [CVE-2025-24813](https://insights.sbomify.com/CVE-2025-24813/): Apache Tomcat Path Equivalence (critical 10.0, exploited in the wild)
- [CVE-2016-8735](https://insights.sbomify.com/CVE-2016-8735/): Apache Tomcat Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2017-12617](https://insights.sbomify.com/CVE-2017-12617/): Apache Tomcat Remote Code Execution (high 8.1, exploited in the wild)
- [CVE-2017-12615](https://insights.sbomify.com/CVE-2017-12615/): Apache Tomcat on Windows Remote Code Execution (high 8.1, exploited in the wild)
- [CVE-2026-34486](https://insights.sbomify.com/CVE-2026-34486/): Apache Tomcat Missing Encryption of Sensitive Data (high 7.5, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2012-2733 and fix it if it is affected.

What it is: CVE-2012-2733 is a medium-severity denial of service vulnerability in Apache Tomcat, published on 16 Nov 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-2012-2733 in the wild and no public exploit code.

Affected product: Apache Tomcat. 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-2012-2733/ (Markdown: https://insights.sbomify.com/CVE-2012-2733/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2012-2733
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2012-2733
- OSV: https://osv.dev/vulnerability/CVE-2012-2733

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From sbomify Insights: https://insights.sbomify.com/CVE-2012-2733/
Summaries are generated and may contain mistakes; the official description above is the record.