Critical 9.1Published Feb 24, 2026

CVE-2026-27586Caddy is an extensible server platform that uses TLS by default.

Updated under an hour ago (2026-10-19 09:00 UTC)

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No exploitation reported and no EPSS estimate yet.

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Every CVE for caddyserver caddy

Exploited in the last 30 days

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.

CVSS: 9.1 CRITICAL (v3.1, NVD)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Weakness (CWE): CWE-755
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Not given
NVD analysis: Analyzed
Record last updated: Jun 17, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

caddyserver caddy caddyserver:caddy	before 2.11.1	NVD

References

https://gist.github.com/moscowchill/9566c79c76c0b64c57f8bd0716f97c48exploit
https://github.com/caddyserver/caddy/releases/tag/v2.11.1release-notes
https://github.com/caddyserver/caddy/security/advisories/GHSA-hffm-g8v7-wrv7exploit, vendor-advisory

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.