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Vulnerabilities / CVE-2026-27586

critical

CVE-2026-27586

Caddy is an extensible server platform that uses TLS by default. Prior ...

Published Modified CWE 755
In the Trivy database since at least 24 Oct 2026, 07:11 UTCWhen it arrived before that build is not recorded.

Severity by source

NVD9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
GHSA8.8CVSS: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

Trivy's own label is CRITICAL. Rated critical by NVD. Rated lower by GHSA (high).

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 packages and fixed versions

SourcePackageFixed in
alpine 3.23caddy2.11.2-r0
alpine 3.24caddy2.11.1-r0
alpine edgecaddy2.11.1-r0
debian 14caddy2.11.2-1
go::GitHub Security Advisory Gogithub.com/caddyserver/caddy/v22.11.1
minimoscaddy2.11.1-r0
rapidfort alpine 3.20caddy2.11.1-r0
rapidfort alpine 3.21caddy2.11.1-r0
rapidfort alpine 3.22caddy2.11.1-r0
rapidfort alpine 3.23caddy2.11.1-r0
rapidfort debian 12caddy0:2.11.2-1
rapidfort debian 13caddy0:2.11.2-1
Show all 17 entries from 17 sources
SourcePackageFixed in
alpine 3.23caddy2.11.2-r0
alpine 3.24caddy2.11.1-r0
alpine edgecaddy2.11.1-r0
debian 14caddy2.11.2-1
go::GitHub Security Advisory Gogithub.com/caddyserver/caddy/v22.11.1
minimoscaddy2.11.1-r0
rapidfort alpine 3.20caddy2.11.1-r0
rapidfort alpine 3.21caddy2.11.1-r0
rapidfort alpine 3.22caddy2.11.1-r0
rapidfort alpine 3.23caddy2.11.1-r0
rapidfort debian 12caddy0:2.11.2-1
rapidfort debian 13caddy0:2.11.2-1
rapidfort fedora 43caddy2.10.2-9.fc43
rapidfort Oracle Linux 10caddy2.10.2-9.el10_3
rapidfort ubuntu 20.04caddy0:2.11.2-1
rapidfort ubuntu 22.04caddy0:2.11.2-1
rapidfort ubuntu 24.04caddy0:2.11.2-1

References

Vulnerability data compiled from the Trivy vulnerability database (trivy-db, Aqua Security, Apache License 2.0), which aggregates third-party advisories. CVE records are published by The MITRE Corporation under the CVE Terms of Use; CVE is a trademark of MITRE. This product uses data from the NVD API but is not endorsed or certified by the NVD. Severity, titles and advisory data from the GitHub Advisory Database (CC BY 4.0), Red Hat security data (CC BY 4.0) and the other sources linked on each entry. Entries may be summarised or re-formatted; the linked original is the authoritative record.