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.
References
| Link | Resource |
|---|---|
| https://github.com/caddyserver/caddy/releases/tag/v2.11.1 | Release Notes |
| https://github.com/caddyserver/caddy/security/advisories/GHSA-5r3v-vc8m-m96g | Exploit Vendor Advisory |
| https://github.com/php/frankenphp/security/advisories/GHSA-g966-83w7-6w38 | Third Party Advisory |
Configurations
History
25 Feb 2026, 17:07
| Type | Values Removed | Values Added |
|---|---|---|
| First Time |
Caddyserver
Caddyserver caddy |
|
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 9.8 |
| CPE | cpe:2.3:a:caddyserver:caddy:*:*:*:*:*:*:*:* | |
| References | () https://github.com/caddyserver/caddy/releases/tag/v2.11.1 - Release Notes | |
| References | () https://github.com/caddyserver/caddy/security/advisories/GHSA-5r3v-vc8m-m96g - Exploit, Vendor Advisory | |
| References | () https://github.com/php/frankenphp/security/advisories/GHSA-g966-83w7-6w38 - Third Party Advisory |
24 Feb 2026, 17:29
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-02-24 17:29
Updated : 2026-02-25 17:07
NVD link : CVE-2026-27590
Mitre link : CVE-2026-27590
CVE.ORG link : CVE-2026-27590
JSON object : View
Products Affected
caddyserver
- caddy