# CVE-2026-20337: ClamAV ZIP File Format Processing Memory Corruption Vulnerability

> An unauthenticated remote attacker can cause a denial of service by submitting a crafted zip file that triggers an out-of-bounds write in the ClamAV scanner.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/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:** 7 Aug 2026
- **Updated:** 7 Aug 2026
- **Also known as:** AZL-95456, GHSA-rhg3-hwfw-hp7p, UBUNTU-CVE-2026-20337

## What is CVE-2026-20337?

CVE-2026-20337 is a high-severity memory corruption vulnerability in Cisco Secure Endpoint, published on 7 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability in the zip archive parser of ClamAV could allow an unauthenticated, remote attacker to cause a DoS condition on an affected device.

This vulnerability is due to improper boundary checks for content in zip files during scanning, which may result in an out-of-bounds write condition. An attacker could exploit this vulnerability by submitting a crafted zip file for scanning. A successful exploit could allow the attacker to cause the ClamAV scanning process to terminate, resulting in a DoS condition on the affected software.

Weakness: CWE-120 (Buffer Copy without Checking Size of Input)

## Which versions are affected by CVE-2026-20337?


## How do I fix CVE-2026-20337?

Upgrade to a fixed version.

## Is CVE-2026-20337 being exploited?

There is no known exploitation of CVE-2026-20337 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-20337 and fix it if it is affected.

What it is: CVE-2026-20337 is a high-severity memory corruption vulnerability in Cisco Secure Endpoint, published on 7 Aug 2026. 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-2026-20337 in the wild and no public exploit code.

Affected product: Cisco Secure Endpoint. 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-2026-20337/ (Markdown: https://insights.sbomify.com/CVE-2026-20337/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-20337
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-20337
- OSV: https://osv.dev/vulnerability/CVE-2026-20337

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-20337/
Summaries are generated and may contain mistakes; the official description above is the record.