{"id":"CVE-2026-3591","details":"A use-after-return vulnerability exists in the `named` server when handling DNS queries signed with SIG(0). Using a specially-crafted DNS request, an attacker may be able to cause an ACL to improperly (mis)match an IP address. In a default-allow ACL (denying only specific IP addresses), this may lead to unauthorized access. Default-deny ACLs should fail-secure.\nThis issue affects BIND 9 versions 9.20.0 through 9.20.20, 9.21.0 through 9.21.19, and 9.20.9-S1 through 9.20.20-S1.\nBIND 9 versions 9.18.0 through 9.18.46 and 9.18.11-S1 through 9.18.46-S1 are NOT affected.","modified":"2026-07-08T08:12:58.702911420Z","published":"2026-03-25T14:16:37.297Z","related":["SUSE-SU-2026:1351-1","SUSE-SU-2026:21204-1","openSUSE-SU-2026:10448-1","openSUSE-SU-2026:20550-1"],"database_specific":{},"references":[{"type":"ADVISORY","url":"https://kb.isc.org/docs/cve-2026-3591"},{"type":"FIX","url":"https://downloads.isc.org/isc/bind9/9.20.21"},{"type":"FIX","url":"https://downloads.isc.org/isc/bind9/9.21.20"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/isc-projects/bind9","events":[{"introduced":"14bbdfc7b9db0870a0b8941ca8812d9983fdba1a"},{"fixed":"12f97d4162d435940598de4870d0088b8e6d266c"},{"introduced":"b732da695eecc0526950e2c722cde0bf23e5a070"},{"fixed":"3e7037ceef40688d5b4eb4a55a9df80c7547dd9f"}],"database_specific":{"source":"CPE_RANGE","cpe":"cpe:2.3:a:isc:bind:*:*:*:*:-:*:*:*","extracted_events":[{"introduced":"9.20.0"},{"fixed":"9.20.21"},{"introduced":"9.21.0"},{"fixed":"9.21.20"}]}}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-3591.json"}},{"ranges":[{"type":"GIT","repo":"https://gitlab.isc.org/isc-projects/bind9","events":[{"introduced":"14bbdfc7b9db0870a0b8941ca8812d9983fdba1a"},{"fixed":"12f97d4162d435940598de4870d0088b8e6d266c"},{"introduced":"b732da695eecc0526950e2c722cde0bf23e5a070"},{"fixed":"3e7037ceef40688d5b4eb4a55a9df80c7547dd9f"}],"database_specific":{"source":"CPE_RANGE","cpe":"cpe:2.3:a:isc:bind:*:*:*:*:-:*:*:*","extracted_events":[{"introduced":"9.20.0"},{"fixed":"9.20.21"},{"introduced":"9.21.0"},{"fixed":"9.21.20"}]}}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-3591.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N"}]}