{"id":"CVE-2026-11721","details":"It is possible for an attacker's zone to respond to a query with an RRSIG that has a smaller number of labels than the zone in which the RRSIG is contained. This causes `named` to produce a wildcard name for a zone that is shorter than the attacker's zone, which can result in cache poisoning. For this attack to have any effect, the resolver under attack must have set `synth-from-dnssec yes;` (which is the default).\nThis issue affects BIND 9 versions 9.11.0 through 9.18.50, 9.20.0 through 9.20.24, 9.21.0 through 9.21.23, 9.11.3-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.24-S1.","modified":"2026-11-04T02:47:24.764001886Z","published":"2026-07-22T15:16:51.837Z","related":["ALSA-2026:54509","ALSA-2026:54510","ALSA-2026:54654","ALSA-2026:55437","ALSA-2026:55442","SUSE-SU-2026:3426-1","SUSE-SU-2026:3452-1","SUSE-SU-2026:3476-1","SUSE-SU-2026:3477-1","SUSE-SU-2026:3484-1","SUSE-SU-2026:3517-1","SUSE-SU-2026:3554-1","openSUSE-SU-2026:11375-1","openSUSE-SU-2026:21489-1"],"database_specific":{},"references":[{"type":"WEB","url":"https://downloads.isc.org/isc/bind9/9.20.26"},{"type":"WEB","url":"https://downloads.isc.org/isc/bind9/9.21.24"},{"type":"ADVISORY","url":"https://kb.isc.org/docs/cve-2026-11721"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/isc-projects/bind9","events":[{"introduced":"1477c19dd9a347ee19a42dac227f299a4680506f"},{"last_affected":"ad1a84a99f853f5194ec0afc52a152f2b9579074"},{"introduced":"a37581543167cd471036b0d43e767c9ffb825625"},{"last_affected":"ad1a84a99f853f5194ec0afc52a152f2b9579074"},{"introduced":"14bbdfc7b9db0870a0b8941ca8812d9983fdba1a"},{"last_affected":"e5d43f1764259da929f6c0200a9db2081141998a"},{"introduced":"98f2a5b7f486829b5644e5e9d6119c8cfefcdf70"},{"last_affected":"e5d43f1764259da929f6c0200a9db2081141998a"},{"introduced":"b732da695eecc0526950e2c722cde0bf23e5a070"},{"last_affected":"ef0603035791f16bc3bb7de20099b7b4434a24cb"}],"database_specific":{"extracted_events":[{"range":[{"introduced":"9.11.0"},{"last_affected":"9.18.50"}],"source":"CPE_RANGE","cpe":"cpe:2.3:a:isc:bind:*:*:*:*:-:*:*:*"},{"source":"CPE_RANGE","cpe":"cpe:2.3:a:isc:bind:*:*:*:*:supported_preview:*:*:*","range":[{"introduced":"9.11.3"},{"last_affected":"9.18.50"}]},{"source":"CPE_RANGE","cpe":"cpe:2.3:a:isc:bind:*:*:*:*:-:*:*:*","range":[{"introduced":"9.20.0"},{"last_affected":"9.20.24"}]},{"cpe":"cpe:2.3:a:isc:bind:*:*:*:*:supported_preview:*:*:*","range":[{"introduced":"9.20.9"},{"last_affected":"9.20.24"}],"source":"CPE_RANGE"},{"source":"CPE_RANGE","cpe":"cpe:2.3:a:isc:bind:*:*:*:*:-:*:*:*","range":[{"introduced":"9.21.0"},{"last_affected":"9.21.23"}]}]}}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-11721.json"}},{"ranges":[{"type":"GIT","repo":"https://gitlab.isc.org/isc-projects/bind9","events":[{"introduced":"1477c19dd9a347ee19a42dac227f299a4680506f"},{"last_affected":"ad1a84a99f853f5194ec0afc52a152f2b9579074"},{"introduced":"a37581543167cd471036b0d43e767c9ffb825625"},{"last_affected":"ad1a84a99f853f5194ec0afc52a152f2b9579074"},{"introduced":"14bbdfc7b9db0870a0b8941ca8812d9983fdba1a"},{"last_affected":"e5d43f1764259da929f6c0200a9db2081141998a"},{"introduced":"98f2a5b7f486829b5644e5e9d6119c8cfefcdf70"},{"last_affected":"e5d43f1764259da929f6c0200a9db2081141998a"},{"introduced":"b732da695eecc0526950e2c722cde0bf23e5a070"},{"last_affected":"ef0603035791f16bc3bb7de20099b7b4434a24cb"}],"database_specific":{"extracted_events":[{"cpe":"cpe:2.3:a:isc:bind:*:*:*:*:-:*:*:*","range":[{"introduced":"9.11.0"},{"last_affected":"9.18.50"}],"source":"CPE_RANGE"},{"cpe":"cpe:2.3:a:isc:bind:*:*:*:*:supported_preview:*:*:*","range":[{"introduced":"9.11.3"},{"last_affected":"9.18.50"}],"source":"CPE_RANGE"},{"source":"CPE_RANGE","cpe":"cpe:2.3:a:isc:bind:*:*:*:*:-:*:*:*","range":[{"introduced":"9.20.0"},{"last_affected":"9.20.24"}]},{"source":"CPE_RANGE","cpe":"cpe:2.3:a:isc:bind:*:*:*:*:supported_preview:*:*:*","range":[{"introduced":"9.20.9"},{"last_affected":"9.20.24"}]},{"cpe":"cpe:2.3:a:isc:bind:*:*:*:*:-:*:*:*","range":[{"introduced":"9.21.0"},{"last_affected":"9.21.23"}],"source":"CPE_RANGE"}]}}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-11721.json"}}],"schema_version":"1.9.2","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"}]}