CVE-2026-5946

Description

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.

CVSS breakdown

Affected products

• isc / bind9.11.0 – 9.16.50
• isc / BIND 99.18.0 – 9.18.48
• isc / BIND 99.20.0 – 9.20.22
• isc / BIND 99.21.0 – 9.21.21
• isc / BIND 99.11.0 – 9.16.50
• isc / BIND 99.18.11-S1 – 9.18.48-S1
• isc / BIND 99.20.9-S1 – 9.20.22-S1
• isc / BIND 99.11.3-S1 – 9.16.50-S1

References

• MISChttps://kb.isc.org/docs/cve-2026-5946
• MISChttps://downloads.isc.org/isc/bind9/9.18.49
• MISChttps://downloads.isc.org/isc/bind9/9.20.23
• MISChttps://downloads.isc.org/isc/bind9/9.21.22