CVE-2026-18922Critical authentication bypass in 389 Directory Server
A flaw was found in 389 Directory Server. During SASL PLAIN authentication, a stale identity carried in a Cyrus SASL auxiliary property from a prior failed bind attempt can be installed on a connection following a subsequent, unrelated successful bind, regardless of which SASL mechanism completes that second bind. An attacker can send a SASL PLAIN bind as cn=Directory Manager with an incorrect password, then complete a SASL ANONYMOUS bind on the same connection, causing the server to grant Directory Manager authority without any valid credentials. A variant using a valid low-privileged account's own successful bind instead of an anonymous one is also possible.
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A critical vulnerability in 389 Directory Server allows an attacker to gain full administrative (Directory Manager) authority without valid credentials. The flaw involves a stale identity being incorrectly applied to a connection after a failed SASL bind followed by an anonymous or low-privileged successful bind.
Relevant roles
Severity
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HCWE-287EPSS
No EPSS score yet (CVE may be too fresh).
Technical description
A flaw was found in 389 Directory Server. During SASL PLAIN authentication, a stale identity carried in a Cyrus SASL auxiliary property from a prior failed bind attempt can be installed on a connection following a subsequent, unrelated successful bind, regardless of which SASL mechanism completes that second bind. An attacker can send a SASL PLAIN bind as cn=Directory Manager with an incorrect password, then complete a SASL ANONYMOUS bind on the same connection, causing the server to grant Directory Manager authority without any valid credentials. A variant using a valid low-privileged account's own successful bind instead of an anonymous one is also possible.