CVE catalog
CVE-2026-27586
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 sil
- Severity
- High · CVSS 8.8
- Published
- Source
- [NVD] · [CVE record]
- EPSS
- 0.29% · Oct 27, 2026
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.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | caddy | sid | 2.11.4-1 | fixed |
| Debian | caddy | forky | 2.11.4-1 | fixed |
| Debian | caddy | trixie | 2.6.2-12+deb13u1 | not affected |
| Debian | caddy | trixie-security | 2.6.2-12+deb13u1 | not affected |
| Debian | caddy | bookworm | 2.6.2-5 | not affected |
| Debian | caddy | bookworm-security | 2.6.2-5+deb12u1 | not affected |
| Go | github.com/caddyserver/caddy/v2/modules/caddytls | Not reported | 2.11.1 | fixed |
| Cpe | caddy | Not reported | Not reported | vulnerable |
| Go | github.com/caddyserver/caddy/v2 | Not reported | 2.11.1 | fixed |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | caddy | source | sid | 2.11.2-1 | not yet assigned | Not reported | [1132041] |
| Debian | caddy | source | forky | 2.11.2-1 | not yet assigned | Not reported | [1132041] |
| Debian | caddy | source | trixie | Not affected | unimportant | Not reported | [1132041] |
| Debian | caddy | source | bookworm | Not affected | unimportant | Not reported | [1132041] |
| Go | github.com/caddyserver/caddy/v2/modules/caddytls | go | Not reported | 2.11.1 | Not reported | Not reported | Not reported |
| Go | github.com/caddyserver/caddy/v2 | Go | Not reported | 2.11.1 | Not reported | Not reported | Not reported |
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [caddy]Not affected
Details (2)
2.6.2-5· amd64 · bookwormNot affected
nvd · caddy · debian · bookworm
2.6.2-5· arm64 · bookwormNot affected
nvd · caddy · debian · bookworm
Observed:
References
- [https://github.com/advisories/GHSA-hffm-g8v7-wrv7]
- [https://nvd.nist.gov/vuln/detail/CVE-2026-27586]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-27586]
- [https://pkg.go.dev/vuln/GO-2026-4539]
- [https://security-tracker.debian.org/tracker/CVE-2026-27586]
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-27586.json]
[Debian Security Tracker] · [FIRST EPSS] · [GitHub Advisory Database] · [Go Vulnerability Database] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX]