CVE-2021-29432: Matrix Sydent

Medium severity, CVSS 5.7. EPSS: 0.9% chance of exploitation in the next 30 days.

Sydent is a reference matrix identity server. A malicious user could abuse Sydent to send out arbitrary emails from the Sydent email address. This could be used to construct plausible phishing emails, for example. This issue has been fixed in 4469d1d.

Affected products

• Matrix Sydent: before 2.3.0 (fixed in 2.3.0)

Published 2021-04-15. Last modified 2026-06-17.