CVE-2009-0021: Ntp

Medium severity, CVSS 5.0. EPSS: 3.2% chance of exploitation in the next 30 days.

NTP 4.2.4 before 4.2.4p5 and 4.2.5 before 4.2.5p150 does not properly check the return value from the OpenSSL EVP_VerifyFinal function, which allows remote attackers to bypass validation of the certificate chain via a malformed SSL/TLS signature for DSA and ECDSA keys, a similar vulnerability to CVE-2008-5077.

Affected products

• Ntp Ntp: up to and including 4.2.4p4; version 4.2.0 only; version 4.2.2 only; version 4.2.4p1 only; version 4.2.4p2 only; version 4.2.4p3 only

Published 2009-01-07. Last modified 2026-06-16.