CVE-2026-27586
CriticalSummary
Caddy to rozbudowana platforma serwerowa, która domyślnie używa TLS. W wersjach przed 2.11.1, dwa zignorowane błędy w `ClientAuthentication.provision()` powodują, że uwierzytelnianie certyfikatów klienckich mTLS cicho zawodzi, gdy plik certyfikatu CA jest brakujący, nieczytelny lub uszkodzony.
Risk Assessment
Serwer akceptuje dowolny certyfikat kliencki podpisany przez zaufany CA systemu, co całkowicie omija zamierzony zakres zaufania prywatnego CA. To stwarza poważne ryzyko dla bezpieczeństwa organizacji, ponieważ może prowadzić do nieautoryzowanego dostępu.
Recommendation
Zaleca się aktualizację do wersji 2.11.1, aby naprawić tę podatność. Należy również monitorować i weryfikować dostępność oraz poprawność plików certyfikatów CA, aby uniknąć degradacji bezpieczeństwa.
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Original NVD description (English source)
Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, two swallowed errors in `ClientAuthentication.provision()` cause mTLS client certificate authentication to silently fail open when a CA certificate file is missing, unreadable, or malformed. The server starts without error but accepts any client certificate signed by any system-trusted CA, completely bypassing the intended private CA trust boundary. Any deployment using `trusted_ca_cert_file` or `trusted_ca_certs_pem_files` for mTLS will silently degrade to accepting any system-trusted client certificate if the CA file becomes unavailable. This can happen due to a typo in the path, file rotation, corruption, or permission changes. The server gives no indication that mTLS is misconfigured. Version 2.11.1 fixes the vulnerability.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS