# CVE-2022-20770: ClamAV CHM File Parsing Denial of Service Vulnerability Affecting Cisco Products: April 2022

> Remote attackers can cause a denial of service in ClamAV via malicious CHM files, affecting Cisco AMP for Endpoints and other systems using the library.

- **Severity:** High 8.6 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 4 May 2022
- **Updated:** 6 Nov 2024
- **Also known as:** ALPINE-CVE-2022-20770, AZL-9666, DEBIAN-CVE-2022-20770, GHSA-5443-gj53-cw56, UBUNTU-CVE-2022-20770

## What is CVE-2022-20770?

CVE-2022-20770 is a high-severity denial of service vulnerability in Clamav Clamav, published on 4 May 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

On April 20, 2022, the following vulnerability in the ClamAV scanning library versions 0.103.5 and earlier and 0.104.2 and earlier was disclosed: A vulnerability in CHM file parser of Clam AntiVirus (ClamAV) versions 0.104.0 through 0.104.2 and LTS version 0.103.5 and prior versions could allow an unauthenticated, remote attacker to cause a denial of service condition on an affected device. For a description of this vulnerability, see the ClamAV blog. This advisory will be updated as additional information becomes available.

Weakness: CWE-399

## Which versions are affected by CVE-2022-20770?

It affects 4 products.


Products: Cisco Secure Endpoint, Clamav Clamav, Debian Debian Linux, Fedoraproject Fedora.

## How do I fix CVE-2022-20770?

Upgrade to a fixed version.

## Is CVE-2022-20770 being exploited?

There is no known exploitation of CVE-2022-20770 in the wild and no public exploit code.

## Other vulnerabilities in Clamav Clamav

- [CVE-2023-20032](https://insights.sbomify.com/CVE-2023-20032/): Memory corruption in Cisco Secure Endpoint (critical 9.8)
- [CVE-2026-20348](https://insights.sbomify.com/CVE-2026-20348/): ClamAV XAR File Format Processing Memory Corruption Vulnerability (high 7.5)
- [CVE-2026-20213](https://insights.sbomify.com/CVE-2026-20213/): ClamAV PE File Format Processing Out-of-Bounds Memory Corruption Vulnerability (high 7.5)
- [CVE-2026-20214](https://insights.sbomify.com/CVE-2026-20214/): ClamAV FSG File Format Processing Out-of-Bounds Memory Corruption Vulnerability (high 7.5)
- [CVE-2026-20215](https://insights.sbomify.com/CVE-2026-20215/): ClamAV 7Zip File Format Processing Out-of-Bounds Memory Corruption Vulnerability (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2022-20770 and fix it if it is affected.

What it is: CVE-2022-20770 is a high-severity denial of service vulnerability in Clamav Clamav, published on 4 May 2022. 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-2022-20770 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-2022-20770/ (Markdown: https://insights.sbomify.com/CVE-2022-20770/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-20770
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-20770
- OSV: https://osv.dev/vulnerability/CVE-2022-20770

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-20770/
Summaries are generated and may contain mistakes; the official description above is the record.