CVE-2021-32919: Debian Linux

High severity, CVSS 7.5. EPSS: 1.4% chance of exploitation in the next 30 days.

An issue was discovered in Prosody before 0.11.9. The undocumented dialback_without_dialback option in mod_dialback enables an experimental feature for server-to-server authentication. It does not correctly authenticate remote server certificates, allowing a remote server to impersonate another server (when this option is enabled).

Affected products

• Debian Debian Linux: version 10.0 only
• Fedoraproject Fedora: version 32 only; version 33 only; version 34 only
• Prosody Prosody: from 0.10.0, before 0.11.9 (fixed in 0.11.9)

Published 2021-05-13. Last modified 2026-06-17.