Improper Authentication Affecting caddy package, versions <2.6.2-12+deb13u1


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.29% (22nd percentile)

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  • Snyk IDSNYK-ECHOLATEST-CADDY-18601865
  • published10 Aug 2026
  • disclosed23 Jun 2026

Introduced: 23 Jun 2026

CVE-2026-52845  (opens in a new tab)
CWE-287  (opens in a new tab)
CWE-290  (opens in a new tab)
CWE-444  (opens in a new tab)

How to fix?

Upgrade Echo:latest caddy to version 2.6.2-12+deb13u1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream caddy package and not the caddy package as distributed by Echo. See How to fix? for Echo:latest relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1