CVE-2026-5946 — Invalid handling of CLASS != IN

Description (CNA)

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.

Affected (CNA)

Vendor / product	Versions
ISC / BIND 9	affected 9.11.0 through 9.16.50; affected 9.18.0 through 9.18.48; affected 9.20.0 through 9.20.22; affected 9.21.0 through 9.21.21; affected 9.11.3-S1 through 9.16.50-S1; affected 9.18.11-S1 through 9.18.48-S1; affected 9.20.9-S1 through 9.20.22-S1

CWE

CWE-20, CWE-125, CWE-617, CWE-754, CWE-843

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.

redhat-SADP

A flaw was found in the bind component, specifically within the `named` daemon. This vulnerability allows a remote attacker to send specially crafted Domain Name System (DNS) messages. These messages, which use unusual classes or meta-classes, can trigger assertion failures in the `named` daemon when processed. Successful exploitation leads to an application level Denial of Service (DoS), making the DNS service unavailable.