CVE-2020-24659: Canonical Ubuntu Linux

High severity, CVSS 7.5. EPSS: 3.7% chance of exploitation in the next 30 days.

An issue was discovered in GnuTLS before 3.6.15. A server can trigger a NULL pointer dereference in a TLS 1.3 client if a no_renegotiation alert is sent with unexpected timing, and then an invalid second handshake occurs. The crash happens in the application's error handling path, where the gnutls_deinit function is called after detecting a handshake failure.

Affected products

• Canonical Ubuntu Linux: version 20.04 only
• Fedoraproject Fedora: version 32 only; version 33 only
• GNU Gnutls: before 3.6.15 (fixed in 3.6.15)
• Opensuse Leap: version 15.1 only; version 15.2 only

Published 2020-09-04. Last modified 2026-06-17.