# CVE-2021-27506: Denial of service in n/a

> Attackers can cause a denial of service in Storsmshield Network Security devices by submitting malformed PNG files to the embedded ClamAV engine.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 19 Mar 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-rfvf-cm38-cvx4, OESA-2021-1187

## What is CVE-2021-27506?

CVE-2021-27506 is a medium-severity denial of service vulnerability in Clamav Clamav, published on 19 Mar 2021. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

The ClamAV Engine (version 0.103.1 and below) component embedded in Storsmshield Network Security (SNS) is subject to DoS in case of parsing of malformed png files. This affect Netasq versions 9.1.0 to 9.1.11 and SNS versions 1.0.0 to 4.2.0. This issue is fixed in SNS 3.7.19, 3.11.7 and 4.2.1.

## Which versions are affected by CVE-2021-27506?

It affects 3 products.


Products: Clamav Clamav, Netasq Project Netasq, Stormshield Stormshield Network Security.

## How do I fix CVE-2021-27506?

Upgrade to a fixed version.

## Is CVE-2021-27506 being exploited?

There is no known exploitation of CVE-2021-27506 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-2021-27506 and fix it if it is affected.

What it is: CVE-2021-27506 is a medium-severity denial of service vulnerability in Clamav Clamav, published on 19 Mar 2021. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-27506 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-2021-27506/ (Markdown: https://insights.sbomify.com/CVE-2021-27506/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-27506
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-27506
- OSV: https://osv.dev/vulnerability/CVE-2021-27506

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-27506/
Summaries are generated and may contain mistakes; the official description above is the record.