CVE-2026-35563: Apache Directory LDAP API: LDAP client implementation does not verify if the server certificate matches the intended LDAP hostname

Severity: high (CVSS 8.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-06-01 · updated 2026-07-22
Weakness: CWE-297

Description

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

Affected products

Apache Software Foundation Apache Directory LDAP API: from 2.0.0 before 2.1.7 — fixed in 2.1.7

How to fix

Upgrade to a fixed version: Apache Software Foundation Apache Directory LDAP API 2.1.7. Check the vendor advisory for mitigations.

References

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