CVE-2020-12100: Canonical Ubuntu Linux

High severity, CVSS 7.5. EPSS: 5.3% chance of exploitation in the next 30 days.

In Dovecot before 2.3.11.3, uncontrolled recursion in submission, lmtp, and lda allows remote attackers to cause a denial of service (resource consumption) via a crafted e-mail message with deeply nested MIME parts.

Affected products

• Canonical Ubuntu Linux: version 14.04 only; version 16.04 only; version 18.04 only; version 20.04 only
• Debian Debian Linux: version 9.0 only; version 10.0 only
• Dovecot Dovecot: before 2.3.11.3 (fixed in 2.3.11.3)
• Fedoraproject Fedora: version 31 only; version 32 only; version 33 only

Published 2020-08-12. Last modified 2026-06-17.