CVE-2026-35563
Apache Directory Ldap Api 2.0.0 – 2.1.7
Raw 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:XSummary
CVE-2026-35563 is a high-severity Improper Validation of Certificate with Host Mismatch (CWE-297) vulnerability in Apache Directory Ldap Api. Its CVSS base score is 8.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Adversary-in-the-Middle (T1557); ranked at the 8th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SC-23 (Session Authenticity) and SC-8 (Transmission Confidentiality and Integrity) — see the control section below for these in your framework.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-33569
Vulnerability Data
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…
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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
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V17.2.8
Mitigating Controls (NIST 800-53 r5) AI
Protecting session authenticity structurally requires proper certificate validation to bind the presented certificate to the intended host.
Requiring confidentiality and integrity of transmitted data necessitates correct TLS certificate validation with host-name checking.
Security engineering principles require correct implementation of certificate validation (including hostname matching) when cryptography is used.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Protecting data-in-transit integrity depends on proper certificate validation to prevent MITM.
Secure development practices include coding correct certificate validation logic.
Server/service authentication via certificates directly requires correct host validation.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing can detect missing certificate validation and host-mismatch checks.
Network security controls include certificate validation and host-name verification to prevent man-in-the-middle attacks.
Security of network services requires proper TLS configuration and certificate validation for service endpoints.
Use of cryptography mandates correct implementation of certificate validation and hostname verification.
Application security requirements include secure communication and certificate validation for external services.
Secure system architecture principles require proper certificate validation to protect communications.