CVE-2021-3404: Fedoraproject Fedora

High severity, CVSS 7.8. EPSS: 1.9% chance of exploitation in the next 30 days.

In ytnef 1.9.3, the SwapWord function in lib/ytnef.c allows remote attackers to cause a denial-of-service (and potentially code execution) due to a heap buffer overflow which can be triggered via a crafted file.

Affected products

• Fedoraproject Fedora: version 33 only
• Red Hat Enterprise Linux: version 7.0 only
• Ytnef Project Ytnef: version 1.9.3 only

Published 2021-03-04. Last modified 2026-06-17.