{"id":"CVE-2026-5947","details":"Undefined behavior may result due to a race condition leading to a use-after-free violation.  If BIND receives an incoming DNS message signed with SIG(0), it begins work to validate that signature.  If, during that validation, the \"recursive-clients\" limit is reached (as would occur during a query flood), and that same DNS message is discarded per the limit, there is a brief window of time while the SIG(0) validation may attempt to read the now-discarded DNS message.\nThis issue affects BIND 9 versions 9.20.0 through 9.20.22, 9.21.0 through 9.21.21, and 9.20.9-S1 through 9.20.22-S1.\nBIND 9 versions 9.18.28 through 9.18.49 and 9.18.28-S1 through 9.18.49-S1 are NOT affected.","modified":"2026-05-31T02:56:28.924850Z","published":"2026-05-20T13:16:40.303Z","related":["openSUSE-SU-2026:10874-1"],"references":[{"type":"ADVISORY","url":"https://kb.isc.org/docs/cve-2026-5947"},{"type":"FIX","url":"https://downloads.isc.org/isc/bind9/9.20.23"},{"type":"FIX","url":"https://downloads.isc.org/isc/bind9/9.21.22"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/isc-projects/bind9","events":[{"introduced":"14bbdfc7b9db0870a0b8941ca8812d9983fdba1a"},{"fixed":"7d0b4d4d436e7b950225a533e5bc56d8f935cc1c"},{"introduced":"b732da695eecc0526950e2c722cde0bf23e5a070"},{"fixed":"02a7b2c8a549b79cf885d1a0cda28b74de22d197"}],"database_specific":{"cpe":"cpe:2.3:a:isc:bind:*:*:*:*:-:*:*:*","extracted_events":[{"introduced":"9.20.0"},{"fixed":"9.20.23"},{"introduced":"9.21.0"},{"fixed":"9.21.22"}],"source":"CPE_RANGE"}}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-5947.json"}},{"ranges":[{"type":"GIT","repo":"https://gitlab.isc.org/isc-projects/bind9","events":[{"introduced":"14bbdfc7b9db0870a0b8941ca8812d9983fdba1a"},{"fixed":"7d0b4d4d436e7b950225a533e5bc56d8f935cc1c"},{"introduced":"b732da695eecc0526950e2c722cde0bf23e5a070"},{"fixed":"02a7b2c8a549b79cf885d1a0cda28b74de22d197"}],"database_specific":{"cpe":"cpe:2.3:a:isc:bind:*:*:*:*:-:*:*:*","extracted_events":[{"introduced":"9.20.0"},{"fixed":"9.20.23"},{"introduced":"9.21.0"},{"fixed":"9.21.22"}],"source":"CPE_RANGE"}}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-5947.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}