{"id":"CVE-2026-91768","summary":"IPv6 ACL bypass in FastCGI listen.allowed_clients due to partial address comparison (memcmp 12 bytes)","details":"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.","aliases":["BIT-libphp-2026-91768","BIT-php-2026-91768","BIT-php-min-2026-91768","GHSA-62xp-839h-2637"],"modified":"2026-11-11T02:55:52.863833882Z","published":"2026-09-25T21:07:30.950Z","related":["ALSA-2026:87080","SUSE-SU-2026:24158-1","SUSE-SU-2026:4602-1","SUSE-SU-2026:4603-1","SUSE-SU-2026:4651-1","SUSE-SU-2026:4853-1","openSUSE-SU-2026:11901-1","openSUSE-SU-2026:22045-1"],"database_specific":{"cwe_ids":["CWE-1023"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/91xxx/CVE-2026-91768.json","cna_assigner":"php"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/91xxx/CVE-2026-91768.json"},{"type":"ADVISORY","url":"https://github.com/php/php-src/security/advisories/GHSA-62xp-839h-2637"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-91768"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/php/php-src","events":[{"introduced":"70ee6c20ad97e02c2b8098aeea96fefbbc3ac5c2"},{"fixed":"0be211a0cf752780881a9611224f8adc516af573"},{"introduced":"d26068059e83fe40de3430a512471d194119bee0"},{"fixed":"2d3433d24d59f45703be2b4fb40d74e5a41b136b"},{"introduced":"b437f2b32eb364c9496d24abcc734272e5c9c980"},{"fixed":"c31ae58ecbedc7a85dac0eee5a6a88da73543e70"},{"introduced":"685e99655ae97c667950f7f7d176985958718f56"},{"fixed":"678778973bb4d4185c06ef1320de50f1a975d3c8"}],"database_specific":{"extracted_events":[{"cpe":"cpe:2.3:a:php:php:*:*:*:*:*:*:*:*","range":[{"introduced":"8.2.0"},{"fixed":"8.2.34"}],"source":"CPE_RANGE"},{"source":"CPE_RANGE","cpe":"cpe:2.3:a:php:php:*:*:*:*:*:*:*:*","range":[{"introduced":"8.3.0"},{"fixed":"8.3.35"}]},{"range":[{"introduced":"8.4.0"},{"fixed":"8.4.26"}],"source":"CPE_RANGE","cpe":"cpe:2.3:a:php:php:*:*:*:*:*:*:*:*"},{"cpe":"cpe:2.3:a:php:php:*:*:*:*:*:*:*:*","range":[{"introduced":"8.5.0"},{"fixed":"8.5.11"}],"source":"CPE_RANGE"}]}}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-91768.json"}}],"schema_version":"1.9.2","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N"}]}