CyberSecBulletin

Caddyserver vulnerabilities

We track 11 vulnerabilities in Caddyserver products. 11 are rated high or critical, and 1 has been exploited in real attacks. The most recent was published on June 23, 2026.

11vulnerabilities
4critical
7high
1exploited
8.4average CVSS score

Latest Caddyserver vulnerabilities

  • 8.1 High severity

    caddy: Improper Authentication

    CVE-2026-52845Caddyserver

    Caddy is an extensible server platform that uses TLS by default. Prior to 2.11.4, forward_auth copy_headers deletes the exact client-supplied identity header before copying the trusted value from the auth gateway. But when the request later goes through php_fa

  • 7.5 High severity

    caddy: Improper Limitation of a Pathname to a Restricted Directory

    CVE-2026-52844Caddyserver

    Caddy is an extensible server platform that uses TLS by default. Prior to 2.11.4, on Windows, Caddy path matchers treat /private\secret.txt as outside /private/*, but file_server later resolves the same request path as private\secret.txt on disk. An unauthenti

  • 8.1 High severity

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

    CVE-2026-45135Caddyserver

    Caddy is an extensible server platform that uses TLS by default. From 2.7.0 until 2.11.3, the FastCGI transport's splitPos() in modules/caddyhttp/reverseproxy/fastcgi/fastcgi.go misuses golang.org/x/text/search with search.IgnoreCase when the request path cont

  • 7.5 High severity

    caddy: Improper Neutralization of Special Elements in Output Used by a Downstream Component

    CVE-2026-30852Caddyserver

    Caddy is an extensible server platform that uses TLS by default. From version 2.7.5 to before version 2.11.2, the vars_regexp matcher in vars.go:337 double-expands user-controlled input through the Caddy replacer. When vars_regexp matches against a placeholder

  • 8.8 High severity

    caddy: Improper Authentication

    CVE-2026-30851Caddyserver

    Caddy is an extensible server platform that uses TLS by default. From version 2.10.0 to before version 2.11.2, forward_auth copy_headers does not strip client-supplied headers, allowing identity injection and privilege escalation. This issue has been patched i

  • 9.8 Critical severity

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

    CVE-2026-27590Caddyserver

    Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, Caddy's FastCGI path splitting logic computes the split index on a lowercased copy of the request path and then uses that byte index to slice the original path. This is u

  • 9.1 Critical severity

    caddy: Improper Handling of Case Sensitivity

    CVE-2026-27588Caddyserver

    Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, Caddy's HTTP `host` request matcher is documented as case-insensitive, but when configured with a large host list (>100 entries) it becomes case-sensitive due to an optim

  • 9.1 Critical severity

    caddy: Improper Handling of Case Sensitivity

    CVE-2026-27587Caddyserver

    Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, Caddy's HTTP `path` request matcher is intended to be case-insensitive, but when the match pattern contains percent-escape sequences (`%xx`) it compares against the reque

  • 9.1 Critical severity

    caddy: Improper Handling of Exceptional Conditions

    CVE-2026-27586Caddyserver

    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, unrea

  • 7.5 High severity

    HTTP/2 Rapid Reset Attack Exploited

    CVE-2023-44487IETFEPSS 100%

    The HTTP/2 protocol allows a denial of service (server resource consumption) because request cancellation can reset many streams quickly, as exploited in the wild in August through October 2023.

  • 7.5 High severity

    Caddy: Out-of-bounds Read

    CVE-2022-34037CaddyserverEPSS 1.18%

    An out-of-bounds read in the rewrite function at /modules/caddyhttp/rewrite/rewrite.go in Caddy v2.5.1 allows attackers to cause a Denial of Service (DoS) via a crafted URI. Note: This has been disputed as a bug, not a security vulnerability, in the Caddy web