# CVE-2012-0840: Denial of service in n/a

> Attackers can cause denial of service via CPU consumption by triggering predictable hash collisions in the Apache Portable Runtime library.

- **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:** 10 Feb 2012
- **Updated:** 6 Aug 2024
- **Also known as:** DEBIAN-CVE-2012-0840, GHSA-x7rw-r7fp-j64f

## What is CVE-2012-0840?

CVE-2012-0840 is a medium-severity denial of service vulnerability in n/a, published on 10 Feb 2012. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

tables/apr_hash.c in the Apache Portable Runtime (APR) library through 1.4.5 computes hash values without restricting the ability to trigger hash collisions predictably, which allows context-dependent attackers to cause a denial of service (CPU consumption) via crafted input to an application that maintains a hash table.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2012-0840?

It affects 1 product.


Products: Apache Portable Runtime.

## How do I fix CVE-2012-0840?

Upgrade to a fixed version.

## Is CVE-2012-0840 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2012-0840 exists.

Public exploit code:

- Apache APR - Hash Collision Denial of Service (exploitdb)

## Other vulnerabilities in n/a

- [CVE-2022-24963](https://insights.sbomify.com/CVE-2022-24963/): Apache Portable Runtime (APR): out-of-bound writes in the apr_encode family of functions (critical 9.8)
- [CVE-2022-28331](https://insights.sbomify.com/CVE-2022-28331/): Apache Portable Runtime (APR): Windows out-of-bounds write in apr_socket_sendv function (critical 9.8)
- [CVE-2021-35940](https://insights.sbomify.com/CVE-2021-35940/): Regression of CVE-2017-12613 (high 7.1)
- [CVE-2017-12613](https://insights.sbomify.com/CVE-2017-12613/): Information disclosure in Apache Portable Runtime (high 7.1)
- [CVE-2023-49582](https://insights.sbomify.com/CVE-2023-49582/): Apache Portable Runtime (APR): Unexpected lax shared memory permissions (medium 5.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2012-0840 and fix it if it is affected.

What it is: CVE-2012-0840 is a medium-severity denial of service vulnerability in n/a, published on 10 Feb 2012. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2012-0840 exists.

Affected product: n/a. 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-2012-0840/ (Markdown: https://insights.sbomify.com/CVE-2012-0840/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2012-0840
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2012-0840
- OSV: https://osv.dev/vulnerability/CVE-2012-0840

---
From sbomify Insights: https://insights.sbomify.com/CVE-2012-0840/
Summaries are generated and may contain mistakes; the official description above is the record.