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Werk #22253: LDAP: first login of a user who does not exist in Checkmk yet failed

Component Setup
Title LDAP: first login of a user who does not exist in Checkmk yet failed
Date Sep 1, 2026
Level Trivial Change
Class Bug Fix
Compatibility Compatible - no manual interaction needed
Checkmk versions & editions
3.0.0b1
Not yet released
Checkmk Community, Checkmk Pro, Checkmk Ultimate, Checkmk Cloud, Checkmk Ultimate MT
2.5.0p13
Not yet released
Checkmk Community, Checkmk Pro, Checkmk Ultimate, Checkmk Cloud, Checkmk Ultimate MT

When a user authenticated with LDAP credentials and did not have a Checkmk user account yet, the login failed with an internal error. Requests to the REST API answered with HTTP 500, and web.log recorded an AssertionError: The session has not yet been opened.

Affected were all logins that trigger a user synchronization while authenticating: the first login of an LDAP user, and any login that changes the synchronized attributes or roles of an existing LDAP user.

The synchronization runs while the user is being authenticated, before Checkmk has opened the user session. It tried to read the acting user from that session, which is not available that early. This has been fixed; the affected synchronizations no longer read the session.

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