CVE-2026-91768
CVE-2026-91768
6.5
MediumPublished:
Last updated:
Source:security@php.net
Awaiting Analysis
Weakness (CWE)
CVSS Vector
v3.1- Attack Vector
- Adjacent
- Attack Complexity
- Low
- Privileges Required
- None
- User Interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
Description
The IPv6 branch of the FastCGI client access check compares only the first 12 bytes of a 16-byte IPv6 address, so listen.allowed_clients matches on a /96 prefix instead of the exact address. An attacker who can source an address sharing the first 96 bits with an allowed one passes the check and reaches the FastCGI endpoint.