Improper Access Control

Caddy is vulnerable to Improper Access Control. The vulnerability is due to incorrect case-insensitive matching in the HTTP host request matcher when large host lists are configured, allowing attackers to modify the casing of the Host header and bypass host-based routing or associated access...

Linux Distros Unpatched Vulnerability : CVE-2026-27588

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available. - 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, b...

Caddy: MatchHost becomes case-sensitive for large host lists (>100), enabling host-based route/auth bypass

Summary 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 optimized matching path. An attacker can bypass host-based routing and any access controls attached to that route by changing the...

GHSA-X76F-JF84-RQJ8 Caddy: MatchHost becomes case-sensitive for large host lists (>100), enabling host-based route/auth bypass

Summary 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 optimized matching path. An attacker can bypass host-based routing and any access controls attached to that route by changing the...

CVE-2026-27588

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 optimized matching path. An attacker can bypass...

CVE-2026-27588

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 optimized matching path. An attacker can bypass...

CVE-2026-27588

CVE-2026-27588 affects Caddy prior to 2.11.1, where the HTTP host matcher becomes case-sensitive when configured with large host lists (>100 entries). This changes the documented case-insensitivity of the host matcher and can allow an attacker to bypass host-based routing and attached access c...

CVE-2026-27588 Caddy: MatchHost becomes case-sensitive for large host lists (>100), enabling host-based route/auth bypass

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 optimized matching path. An attacker can bypass...

CVE-2026-27588 Caddy: MatchHost becomes case-sensitive for large host lists (>100), enabling host-based route/auth bypass

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 optimized matching path. An attacker can bypass...

CVE-2026-27588

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 optimized matching path. An attacker can bypass...

CVE-2026-27588 Caddy: MatchHost becomes case-sensitive for large host lists (>100), enabling host-based route/auth bypass

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 optimized matching path. An attacker can bypass...

PT-2026-21773

Name of the Vulnerable Software and Affected Versions Caddy versions prior to 2.11.1 Description Caddy’s HTTP host request matcher is documented as case-insensitive, but becomes case-sensitive when configured with a large host list more than 100 entries due to an optimized matching path. An...

CVE-2019-19943

The HTTP service in quickweb.exe in Pablo Quick 'n Easy Web Server 3.3.8 allows Remote Unauthenticated Heap Memory Corruption via a large host or domain parameter. It may be possible to achieve remote code execution because of a double free...

Double free

The HTTP service in quickweb.exe in Pablo Quick 'n Easy Web Server 3.3.8 allows Remote Unauthenticated Heap Memory Corruption via a large host or domain parameter. It may be possible to achieve remote code execution because of a double free...

CVE-2019-19240

Embedthis GoAhead before 5.0.1 mishandles redirected HTTP requests with a large Host header. The GoAhead WebsRedirect uses a static host buffer that has a limited length and can overflow. This can cause a copy of the Host header to fail, leaving that buffer uninitialized, which may leak...