Multiple flaws have been identified in `named` related to the handling of DNS messages whose CLASS is not Internet (`IN`) — for example, `CHAOS` or `HESIOD`, or DNS messages that specify meta-classes (`ANY` or `NONE`) in the question section. Specially crafted requests reaching the affected code paths — recursion, dynamic updates (`UPDATE`), zone change notifications (`NOTIFY`), or processing of `IN`-specific record types in non-`IN` data — can cause assertion failures in `named`. This issue affects BIND 9 versions 9.11.0 through 9.16.50, 9.18.0 through 9.18.48, 9.20.0 through 9.20.22, 9.21.0 through 9.21.21, 9.11.3-S1 through 9.16.50-S1, 9.18.11-S1 through 9.18.48-S1, and 9.20.9-S1 through 9.20.22-S1.
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-5946.json
https://kb.isc.org/docs/cve-2026-5946
https://downloads.isc.org/isc/bind9/9.21.22
https://downloads.isc.org/isc/bind9/9.20.23
https://downloads.isc.org/isc/bind9/9.18.49
https://bugzilla.redhat.com/show_bug.cgi?id=2479771
https://access.redhat.com/security/cve/CVE-2026-5946
https://access.redhat.com/errata/RHSA-2026:24368
https://access.redhat.com/errata/RHSA-2026:24367
https://access.redhat.com/errata/RHSA-2026:24339
https://access.redhat.com/errata/RHSA-2026:24338