CVE-2021-3181: Debian Linux

Medium severity, CVSS 6.5. EPSS: 2.8% chance of exploitation in the next 30 days.

rfc822.c in Mutt through 2.0.4 allows remote attackers to cause a denial of service (mailbox unavailability) by sending email messages with sequences of semicolon characters in RFC822 address fields (aka terminators of empty groups). A small email message from the attacker can cause large memory consumption, and the victim may then be unable to see email messages from other persons.

Affected products

• Debian Debian Linux: version 9.0 only; version 10.0 only
• Fedoraproject Fedora: version 32 only; version 33 only
• Mutt Mutt: up to and including 2.0.4

Published 2021-01-19. Last modified 2026-06-17.