CVE search · CVE-2026-27586
CVE-2026-27586
high 8.8
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.
Details
- Status
- Analyzed
- Published
- Last changed
- Source
- security-advisories@github.com
- Weakness
- CWE-755
Severity
| Version | Score | Vector | Source |
|---|---|---|---|
| CVSS 4.0 | high 8.8 | 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 |
security-advisories@github.comSecondary |
| CVSS 3.1 | critical 9.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N |
nvd@nist.govPrimary |
Affected products
Vendor and product from the NVD’s CPE applicability statements. Versions and conditions are on the NVD’s page.
- caddyserver · caddy