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Vulnerability · Published Jun 1, 2026 · Assigned by apache

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

High 8.8

In plain English

A high-severity security flaw in Apache Directory LDAP API from Apache Software Foundation. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 8% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)8.8High
Exploit odds (30 days)0.2%top 92.2% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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 packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12apache-directory-apino fix listedDEBIAN-CVE-2026-35563
Debian:13apache-directory-apino fix listedDEBIAN-CVE-2026-35563
Debian:14apache-directory-apino fix listedDEBIAN-CVE-2026-35563
Mavenorg.apache.directory.api:api-ldap-client-api2.1.8GHSA-85rw-g4f4-jprr
Ubuntu:22.04:LTSapache-directory-apino fix listedUBUNTU-CVE-2026-35563
Ubuntu:24.04:LTSapache-directory-apino fix listedUBUNTU-CVE-2026-35563
Ubuntu:25.10apache-directory-apino fix listedUBUNTU-CVE-2026-35563
Ubuntu:26.04:LTSapache-directory-apino fix listedUBUNTU-CVE-2026-35563
Ubuntu:26.10apache-directory-apino fix listedUBUNTU-CVE-2026-35563

Affected products (as reported)

VendorProductVersions
Apache Software Foundation Apache Directory LDAP API 2.0.0 – through 2.1.7

Weakness: CWE-297 · 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

References