CVE-2026-27587

CRITICAL

Caddy <2.11.1 - Auth Bypass

Title source: llm
STIX 2.1

Description

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 request's escaped path without lowercasing. An attacker can bypass path-based routing and any access controls attached to that route by changing the casing of the request path. Version 2.11.1 contains a fix for the issue.

Scores

CVSS v3 9.1
EPSS 0.0006
EPSS Percentile 18.5%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

CISA SSVC

Vulnrichment
Exploitation poc
Automatable yes
Technical Impact partial

Details

CWE
CWE-178
Status published
Products (2)
caddyserver/caddy 0 - 2.11.1Go
caddyserver/caddy 2.10.2 - 2.11.1
Published Feb 24, 2026
Tracked Since Feb 25, 2026