CVE-2026-35563 PUBLISHED

Apache Directory LDAP API: LDAP client implementation does not verify if the server certificate matches the intended LDAP hostname

Assigner: apache
Reserved: 03.04.2026 Published: 01.06.2026 Updated: 01.06.2026

It was identified that the LDAP client implementation in version 2.1.7 does not verify if the server certificate matches the intended LDAP hostname. While the underlying code validates the certificate chain against a trusted authority, the absence of endpoint identification allows a valid certificate issued for an entirely unrelated host to be improperly accepted. This oversight leaves the connection highly vulnerable to server impersonation and complete connection compromise.

The root cause of this vulnerability lies in the incomplete TLS server identity verification within the LDAP client implementation.

The attacker requires MITM capability on the network to exploit this vulnerability. This attacker must be able to present a certificate trusted by the client's configured trust store.

The hostname verification has been enforced in the new version of the LDAP API

Metrics

CVSS Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:H/SI:L/SA:L
CVSS Score: 8.8

Product Status

Vendor Apache Software Foundation
Product Apache Directory LDAP API
Versions Default: unaffected
  • affected from 2.0.0 to 2.1.7 (incl.)

Credits

  • Rafał Łykowski and Łukasz Kollbek of Qualtrics finder

References

Problem Types

  • CWE-297 Improper Validation of Certificate with Host Mismatch CWE