CVE-2026-27587

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.

Database specific

{
    "cwe_ids": [
        "CWE-178"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27587.json",
    "cna_assigner": "GitHub_M"
}

References

Affected packages

Git / github.com/caddyserver/caddy

Affected ranges

Type

GIT

Repo

https://github.com/caddyserver/caddy

Events

Introduced

551f793700fe1550845c824470b623fd1aa03d36

Fixed

6610e2f1bd8f54853006eefd3849c9965190e57f

Database specific

{
    "cpe": "cpe:2.3:a:caddyserver:caddy:*:*:*:*:*:*:*:*",
    "extracted_events": [
        {
            "introduced": "0"
        },
        {
            "fixed": "2.11.1"
        },
        {
            "introduced": "2.10.2"
        }
    ],
    "source": [
        "AFFECTED_FIELD",
        "CPE_RANGE",
        "REFERENCES"
    ]
}

Affected versions

v2.*

v2.10.2

v2.11.0

v2.11.0-beta.1

v2.11.0-beta.2

Database specific

source

"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-27587.json"