Executive brief
Caddy mTLS authentication fails open in github.com/caddyserver/caddy/v2
Affected products
- Go github.com/caddyserver/caddy/v2
Junglewise Threat Intelligence
CVE-2026-27586: GO-2026-4539 - Caddy mTLS authentication fails open in github.com/caddyserver/caddy/v2
CVE-2026-27586 · Severity: medium · CVSS 4 · Published 2026-02-26
Technologies: github.com/caddyserver/caddy/v2 (Go). Vendors: Go.
Related threats
- Caddy placeholder re-expansion in URI rewrite
- GO-2026-5408 - Caddy: Remote Admin Authorization Bypass on PKI Endpoints via Prefix-Based Path Matching in github.com/caddyserver/caddy
- GO-2026-5730 - Caddy Fix Bypass in github.com/caddyserver/caddy
- Caddyserver Caddy XSS bypass in stripHTML template function
- Caddy authentication bypass via FastCGI header normalization collision