CVE-2021-1252 Clam AntiVirus (ClamAV) Excel XLM Parser Denial of Service Vulnerability
Remote attackers can cause a denial of service in ClamAV by sending crafted Excel files that trigger an infinite loop in the XLM parser.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2021-1252?
CVE-2021-1252 is a high-severity denial of service vulnerability in Clamav Clamav, published on 8 Apr 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Which versions are affected by CVE-2021-1252?
It affects 1 product.
Products include Clamav Clamav.
How do I fix CVE-2021-1252?
Upgrade to a fixed version.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2021-1252 being exploited?
There is no known exploitation of CVE-2021-1252 in the wild and no public exploit code.
Other vulnerabilities in Clamav Clamav
Sources
Also known as ALPINE-CVE-2021-1252, CLEANSTART-2026-YE17561, DEBIAN-CVE-2021-1252, GHSA-5qm5-4fjv-ghcw, UBUNTU-CVE-2021-1252.