CVE-2026-91768

Summary

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.

Affected Software

VendorProductVersion RangeStatus
PHP GroupPHP8.2.* < 8.2.34affected
PHP GroupPHP8.3.* < 8.3.35affected
PHP GroupPHP8.4.* < 8.4.26affected
PHP GroupPHP8.5.* < 8.5.11affected

Weaknesses

  • CWE-1023: CWE-1023

References