CVE-2023-28853: Joinmastodon Mastodon

Medium severity, CVSS 6.5. EPSS: 1.3% chance of exploitation in the next 30 days.

Mastodon is a free, open-source social network server based on ActivityPub Mastodon allows configuration of LDAP for authentication. Starting in version 2.5.0 and prior to versions 3.5.8, 4.0.4, and 4.1.2, the LDAP query made during login is insecure and the attacker can perform LDAP injection attack to leak arbitrary attributes from LDAP database. This issue is fixed in versions 3.5.8, 4.0.4, and 4.1.2.

Affected products

• Joinmastodon Mastodon: from 2.5.0, before 3.5.8 (fixed in 3.5.8); from 4.0.0, before 4.0.4 (fixed in 4.0.4); from 4.1.0, before 4.1.2 (fixed in 4.1.2)

Published 2023-04-04. Last modified 2026-06-17.