CVE-2021-32921: Debian Linux

Medium severity, CVSS 5.9. EPSS: 1.6% chance of exploitation in the next 30 days.

An issue was discovered in Prosody before 0.11.9. It does not use a constant-time algorithm for comparing certain secret strings when running under Lua 5.2 or later. This can potentially be used in a timing attack to reveal the contents of secret strings to an attacker.

Affected products

• Debian Debian Linux: version 9.0 only
• Fedoraproject Fedora: version 32 only; version 33 only; version 34 only
• Prosody Prosody: before 0.11.9 (fixed in 0.11.9)

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