CVE-2026-5946: Invalid handling of CLASS != IN | LiveThreat CVE Feed

High severity · published May 20, 2026

CVE-2026-5946

Invalid handling of CLASS != IN

7.5

CVSS

1.9%

EPSS

On KEV

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 vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack vector

Network

Complexity

Low

Privileges

None

User interaction

None

Confidentiality

None

Integrity

None

Availability

High

Scope

Unchanged

Exploitation

Is it being used?

Exploit prediction (EPSS)1.9% · higher than 80% of CVEs

Exploited in the wildNo evidence yet

CISA KEVNot listed

Ransomware campaign useNot known

Affected products

Which versions

BIND 9 · ISC

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; +1 more · source: vendor

Bind · Isc

9.11.0 through 9.16.50; 9.18.0 before 9.18.49; 9.20.0 before 9.20.23; 9.21.0 before 9.21.22 · source: NVD

Red Hat Enterprise Linux 10 · Red Hat