Vulnerability Database

324,829

Total vulnerabilities in the database

CVE-2026-27586

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.

  • Published: Feb 24, 2026
  • Updated: Feb 26, 2026
  • CVE: CVE-2026-27586
  • Severity: Critical
  • Exploit:

CVSS v3:

  • Severity: Critical
  • Score: 9.1
  • AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

CWEs:

Software From Fixed in
caddyserver / caddy - 2.11.1