# CVE-2011-2721: Integer overflow in n/a

> Remote attackers can crash the ClamAV daemon via a crafted email due to an off-by-one error in hash calculations.

- **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:** 5 Aug 2011
- **Updated:** 6 Aug 2024
- **Also known as:** DEBIAN-CVE-2011-2721, GHSA-x69w-v5wv-rxpx

## What is CVE-2011-2721?

CVE-2011-2721 is a medium-severity vulnerability in Clamav Clamav, published on 5 Aug 2011. 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 cli_hm_scan function in matcher-hash.c in libclamav in ClamAV before 0.97.2 allows remote attackers to cause a denial of service (daemon crash) via an e-mail message that is not properly handled during certain hash calculations.

Weakness: CWE-189

## Which versions are affected by CVE-2011-2721?

It affects 1 product.


Products: Clamav Clamav.

## How do I fix CVE-2011-2721?

Upgrade to a fixed version.

## Is CVE-2011-2721 being exploited?

There is no known exploitation of CVE-2011-2721 in the wild and no public exploit code.

## Other vulnerabilities in Clamav Clamav

- [CVE-2010-0098](https://insights.sbomify.com/CVE-2010-0098/): Security feature bypass in n/a (critical 10.0)
- [CVE-2009-1372](https://insights.sbomify.com/CVE-2009-1372/): Memory corruption in n/a (critical 10.0)
- [CVE-2008-3914](https://insights.sbomify.com/CVE-2008-3914/): Denial of service in n/a (critical 10.0)
- [CVE-2008-0728](https://insights.sbomify.com/CVE-2008-0728/): Memory corruption in n/a (critical 10.0)
- [CVE-2006-1615](https://insights.sbomify.com/CVE-2006-1615/): Other in n/a (critical 10.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2011-2721 and fix it if it is affected.

What it is: CVE-2011-2721 is a medium-severity vulnerability in Clamav Clamav, published on 5 Aug 2011. 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-2011-2721 in the wild and no public exploit code.

Affected product: Clamav Clamav. 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-2011-2721/ (Markdown: https://insights.sbomify.com/CVE-2011-2721/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2011-2721
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2011-2721
- OSV: https://osv.dev/vulnerability/CVE-2011-2721

---
From sbomify Insights: https://insights.sbomify.com/CVE-2011-2721/
Summaries are generated and may contain mistakes; the official description above is the record.