{"id":"CVE-2026-91768","title":"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","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 …","severity":"medium","cvss":6.5,"cvssVector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","cwe":["CWE-1023"],"vendor":"PHP Group","product":"PHP-FPM","affected":["PHP-FPM >= 8.2.* < 8.2.34","PHP-FPM >= 8.3.* < 8.3.35","PHP-FPM >= 8.4.* < 8.4.26","PHP-FPM >= 8.5.* < 8.5.11"],"published":"2026-09-25","updated":"2026-09-25","sourceUpdated":"2026-09-25T22:18:49.807","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-91768","references":[{"url":"https://github.com/php/php-src/security/advisories/GHSA-62xp-839h-2637","label":"security@php.net"}],"tags":["nvd","cve.org"],"ingestedAt":"2026-09-25T21:19:40.216Z","slug":"CVE-2026-91768","body":"## Overview\n\nThe 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":36,"depthScoreParts":{"impact":35.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}