[ldap connector] LDAP search is failing with `tls: handshake error`

[dharapvj]

Preflight Checklist

• I agree to follow the Code of Conduct that this project adheres to.
• I have searched the issue tracker for an issue that matches the one I want to file, without success.
• I am not looking for support or already pursued the available support channels without success.

Version

2.44.0

Storage Type

Kubernetes

Installation Type

Official Helm chart

Expected Behavior

When we try to login to dex with LDAP user, the LDAP login should work fine.

Actual Behavior

When we try to login to dex with LDAP user, the LDAP search fails with below error message:

Login error: failed to connect: LDAP Result Code 200 "Network Error": remote error: tls: handshake failure

I verified that until v2.41.1 existing setup worked fine. from v2.42.0 all releases this issue is coming.

Steps To Reproduce

1. use latest (or any of v2.42.0+) version of dex, use config below for ldap connector, espl the insecureSkipVerify: true part
2. try to login appl which uses dex

Additional Information

No response

Configuration

connectors:
- config:
    bindDN: cn=XXXXXX
    bindPW: XXXXXXXX
    groupSearch:
      baseDN: cn=ROLES,XXXXX
      filter: (objectClass=group)
      groupAttr: member
      nameAttr: cn
      userAttr: DN
    host: example.corp:636
    insecureNoSSL: false
    insecureSkipVerify: true
    userSearch:
      baseDN: O=XXXXX
      emailAttr: mail
      filter: (groupMembership=cn=XXXXXX)
      idAttr: DN
      nameAttr: wchFullName
      username: mail
    usernamePrompt: Email Address
  id: ad
  name: ActiveDirectory
  type: ldap

Logs

time=2026-01-22T11:45:54.880Z level=ERROR msg="failed to login user" err="failed to connect: LDAP Result Code 200 \"Network Error\": remote error: tls: handshake failure" request_id=9dc18d38-90c8-4639-99cf-f4e17f38d8bb

[dharapvj]

Potentially - this PR could have brought this regression?