CVEvulnerability

CVE-2026-52845

8.1 HIGH Published 2026-06-23 Modified 2026-10-25 Official page ↗
Status
Modified
Published
2026-06-23
Last modified
2026-10-25
Assigner
[email protected]
CVSS 3.1 ([email protected])
8.1 HIGH — CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
CVSS 3.1 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)
8.1 HIGH — CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Weaknesses
CWE-287, CWE-290, CWE-444

Description

Caddy is an extensible server platform that uses TLS by default. Prior to 2.11.4, forward_auth copy_headers deletes the exact client-supplied identity header before copying the trusted value from the auth gateway. But when the request later goes through php_fastcgi, Caddy normalizes HTTP headers into CGI variables by replacing - with _. This lets a client send an underscore alias that survives the forward_auth delete step but becomes the same PHP/FastCGI variable. Result: a remote client can inject or sometimes override identity/group headers trusted by PHP/FastCGI applications behind Caddy. This vulnerability is fixed in 2.11.4.

Affected configurations

• caddyserver caddy (< 2.11.4)

Related

Weakness · CWE (3)

  • CWE-287 Improper Authentication weakness
  • CWE-290 Authentication Bypass by Spoofing weakness
  • CWE-444 Inconsistent Interpretation of HTTP Requests weakness

References