Description

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 unsafe for Unicode because `strings.ToLower()` can change UTF-8 byte length for some characters. As a result, Caddy can derive an incorrect `SCRIPT_NAME`/`SCRIPT_FILENAME` and `PATH_INFO`, potentially causing a request that contains `.php` to execute a different on-disk file than intended (path confusion). In setups where an attacker can control file contents (e.g., upload features), this can lead to unintended PHP execution of non-.php files (potential RCE depending on deployment). Version 2.11.1 fixes the issue.

INFO

Published Date :

2026-02-24T16:33:41.353Z

Last Modified :

2026-02-27T20:52:00.327Z

Source :

GitHub_M
AFFECTED PRODUCTS

The following products are affected by CVE-2026-27590 vulnerability.

Vendors Products
Caddyserver
  • Caddy
REFERENCES

Here, you will find a curated list of external links that provide in-depth information to CVE-2026-27590.

URL Resource
https://github.com/caddyserver/caddy/releases/tag/v2.11.1 cve-icon cve-icon
https://github.com/caddyserver/caddy/security/advisories/GHSA-5r3v-vc8m-m96g cve-icon cve-icon
https://github.com/php/frankenphp/security/advisories/GHSA-g966-83w7-6w38 cve-icon cve-icon
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CVSS Vulnerability Scoring System

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Detailed values of each vector for above chart.
Attack Vector
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User Interaction
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Confidentiality Impact
Integrity Impact
Availability Impact