{"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","CWE-940"],"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"],"patched":["hardened_images"],"published":"2026-09-25","updated":"2026-09-29","sourceUpdated":"2026-09-29T21:27:41.130","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"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-91768.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-91768"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2541660"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-91768"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-91768"},{"url":"https://access.redhat.com/errata/RHSA-2026:70720"}],"tags":["nvd","cve.org","csaf","vex","red-hat"],"epss":0.00376,"epssPercentile":0.31443,"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-09-28T12:57:04.931780Z"},"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.\n\n## Vendor advisories\n\n- **RHSA-2026:70720** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-09-23 · [advisory](https://access.redhat.com/errata/RHSA-2026:70720)\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, … · updated 2026-10-01 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-91768.json)","depth":"sunlit","depthScore":36,"depthScoreParts":{"impact":35.8,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}