CVEvulnerability
CVE-2026-27586
8.8 HIGH
Official page ↗
- Status
- Analyzed
- Published
- 2026-02-24
- Last modified
- 2026-06-17
- Assigner
- [email protected]
- CVSS 4.0 ([email protected])
- 8.8 HIGH — CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:P/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:X
- CVSS 3.1 ([email protected])
- 9.1 CRITICAL — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
- Weaknesses
- CWE-755
Description
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.
Affected configurations
• caddyserver caddy (< 2.11.1)
Related
Weakness · CWE (1)
- CWE-755 Improper Handling of Exceptional Conditions weakness