CVE-2018-20217: Debian Linux

Medium severity, CVSS 5.3. EPSS: 1.4% chance of exploitation in the next 30 days.

A Reachable Assertion issue was discovered in the KDC in MIT Kerberos 5 (aka krb5) before 1.17. If an attacker can obtain a krbtgt ticket using an older encryption type (single-DES, triple-DES, or RC4), the attacker can crash the KDC by making an S4U2Self request.

Affected products

• Debian Debian Linux: version 8.0 only; version 9.0 only
• Mit Kerberos: before 5-1.17 (fixed in 5-1.17)

Published 2018-12-26. Last modified 2026-06-17.