[JENKINS-72732] ActiveDirectory authentication error with german umlaut in user DN

[jenkins-infra-bot]

Hi.

I am using Ldap plugin to authenticate to ActiveDirectory, and all users not having german umlaut like "ÄÖÜ" in their user-dn can login fine:

For example:
DN: CN=Franz Tester,OU=Users,DC=example,DC=com

sAMAccountName: tester201

( please see Picture1 too)

All users, with ÜÖÄ in its surname or lastname get an authentication error.

DN:: base64 encoded string

sAMAccountName: tester202

( please see Picture2 too)

I know, it is recommended not to use german umlaut in the DN, but my company has configured it like this, and i cannot change it.
I am not a developer, so i cannot help to fix this problem, but i hope someone is here to help me.
I have tested several configurations with different ldap queries and changed my password to something simple, but nothing works. So i have no further idea and think, it could be a problem with the plugin code to not decode the DN correctly, maybe.

Thank's in advance for your help!

---

Originally reported by jcb, imported from: ActiveDirectory authentication error with german umlaut in user DN

• status: Open
• priority: Critical
• component(s): ldap-plugin
• resolution: Unresolved
• votes: 0
• watchers: 1
• imported: 2025-12-09

Raw content of original issue

Hi.

I am using Ldap plugin to authenticate to ActiveDirectory, and all users not having german umlaut like "ÄÖÜ" in their user-dn can login fine:

For example:
DN: CN=Franz Tester,OU=Users,DC=example,DC=com

sAMAccountName: tester201

( please see Picture1 too)

All users, with ÜÖÄ in its surname or lastname get an authentication error.

DN:: base64 encoded string

sAMAccountName: tester202

( please see Picture2 too)

I know, it is recommended not to use german umlaut in the DN, but my company has configured it like this, and i cannot change it.
I am not a developer, so i cannot help to fix this problem, but i hope someone is here to help me.
I have tested several configurations with different ldap queries and changed my password to something simple, but nothing works. So i have no further idea and think, it could be a problem with the plugin code to not decode the DN correctly, maybe.

Thank's in advance for your help!

environment

Openjdk-21<br/>
RHEL 9.3<br/>
Jenkins 2.426.3<br/>
LDAP plugin: latest

3 attachments

• Java_log.txt
• Picture1.png

  

• Picture2.png