Interpretation Conflict in Caddy - #VU163189
Published: November 9, 2026
Vulnerability identifier: #VU163189
CSH Severity: Medium
CVSS v4: 8.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-436
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows an unauthenticated remote attacker to bypass path-based authorization and execute protected PHP scripts, exposing sensitive output.
The vulnerability exists due to inconsistent path interpretation between Caddy's access-control matchers and FastCGI transport when php_fastcgi skips rewriting, including when the configured index file is absent. An unauthenticated remote attacker can send a dot-segment request ending in a nonexistent PHP path to execute an existing protected script without credentials.
Affected software
Caddy
Remediation
Install security update from vendor's website.
Caddy - update to 2.11.8