# CVE-2011-2939: Memory corruption in n/a

> A heap-based buffer overflow in the Perl Encode module allows attackers to cause a denial of service via crafted Unicode strings.

- **Severity:** Medium 5.1 (`AV:N/AC:H/Au:N/C:P/I:P/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:** 13 Jan 2012
- **Updated:** 6 Aug 2024
- **Also known as:** DEBIAN-CVE-2011-2939, GHSA-76hr-qp66-cq6j

## What is CVE-2011-2939?

CVE-2011-2939 is a medium-severity memory corruption vulnerability in n/a, published on 13 Jan 2012. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Off-by-one error in the decode_xs function in Unicode/Unicode.xs in the Encode module before 2.44, as used in Perl before 5.15.6, might allow context-dependent attackers to cause a denial of service (memory corruption) via a crafted Unicode string, which triggers a heap-based buffer overflow.

Weakness: CWE-189

## Which versions are affected by CVE-2011-2939?

It affects 2 products.


Products: Dan Kogai Encode Module, Perl Perl.

## How do I fix CVE-2011-2939?

Upgrade to a fixed version.

## Is CVE-2011-2939 being exploited?

There is no known exploitation of CVE-2011-2939 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2011-2939 and fix it if it is affected.

What it is: CVE-2011-2939 is a medium-severity memory corruption vulnerability in n/a, published on 13 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-2011-2939 in the wild and no public exploit code.

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-2011-2939/ (Markdown: https://insights.sbomify.com/CVE-2011-2939/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2011-2939
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2011-2939
- OSV: https://osv.dev/vulnerability/CVE-2011-2939

---
From sbomify Insights: https://insights.sbomify.com/CVE-2011-2939/
Summaries are generated and may contain mistakes; the official description above is the record.