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Vulnerability · Published Feb 24, 2026 · Assigned by GitHub_M

CVE-2026-27587Caddy: MatchPath %xx (escaped-path) branch skips case normalization, enabling path-based route/auth bypass

High 7.7

In plain English

A high-severity security flaw in caddy from caddyserver. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 37% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)7.7High
Exploit odds (30 days)0.4%top 63.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Alpine:v3.23caddy2.11.2-r0ALPINE-CVE-2026-27587
Alpine:v3.24caddy2.11.1-r0ALPINE-CVE-2026-27587
Debian:12caddy2.6.2-5+deb12u1DEBIAN-CVE-2026-27587
Debian:13caddy2.6.2-12+deb13u1DEBIAN-CVE-2026-27587
Debian:14caddy2.11.2-1DEBIAN-CVE-2026-27587
Gogithub.com/caddyserver/caddy/v22.11.1GO-2026-4538
Gogithub.com/caddyserver/caddy/v22.11.1GHSA-g7pc-pc7g-h8jh
Ubuntu:25.10caddyno fix listedUBUNTU-CVE-2026-27587
Ubuntu:26.10caddyno fix listedUBUNTU-CVE-2026-27587

Affected products (as reported)

VendorProductVersions
caddyserver caddy < 2.11.1

Weakness: CWE-178 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P

References