Vulnerability Report

CVE-2026-5946

Title: BIND 9 Assertion Failure via Crafted DNS Messages

Input Validation Error

Proof Of Concept

No public PoC currently indexed for CVE-2026-5946.

CWE Category CWE-20

Published Date May 20, 2026

Modified Date May 21, 2026

Exploit Status Not Found

Score 7.5 CVSS v3.1

Exploit Probability (EPSS)

0.07%

Vulnerability Summary

CVE-2026-5946: 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.

Impacted Vendors

isc 1

Reference Links

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

CVSS v3.1

Source Entity [email protected]

Severity HIGH

7.5

Attack Vector

NETWORK

Complexity

LOW

Privileges

N/A

Interaction

NONE

Confidentiality

N/A

Integrity

N/A

Availability

N/A

Scope

UNCHANGED

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

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2026-5946 Exploits & PoCs (Proof Of Concept)

No public PoCs found in our database for this CVE.

May 21, 2026 MODIFIED

Vulnerability data updated via NVD.

May 20, 2026 MODIFIED

Vulnerability data updated via NVD.

May 20, 2026 MODIFIED

Vulnerability data updated via NVD.

Attack Vector Matrix

Access Vector NETWORK

Complexity LOW

Privileges N/A

Interaction NONE

CVSS Vector String


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

Affected Stack

No specific products linked.