9.1

CVE-2026-27586

Exploit

Caddy's mTLS client authentication silently fails open when CA certificate file is missing or malformed

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.
Daten sind bereitgestellt durch National Vulnerability Database (NVD)
Caddyserver ≫ Caddy Version < 2.11.1
VulnDex Vulnerability Enrichment
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Zu dieser CVE wurde keine Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.27% 0.181
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
nvd@nist.gov 9.1 3.9 5.2
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
security-advisories@github.com 8.8 0 0
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
CWE-755 Improper Handling of Exceptional Conditions

The product does not handle or incorrectly handles an exceptional condition.

https://github.com/caddyserver/caddy/releases/tag/v2.11.1
Release Notes
https://github.com/caddyserver/caddy/security/advisories/GHSA-hffm-g8v7-wrv7
Vendor Advisory
Exploit
https://gist.github.com/moscowchill/9566c79c76c0b64c57f8bd0716f97c48
Exploit