Invalid handling of CLASS != IN_CVE-2026-5946

7.5 / 10

HIGH

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

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.

Basic Information

ID CVE-2026-5946

Source isc

Published May 20, 2026 at 13:10

Affected Product

Vendor ISC

Product BIND 9

Version 9.11.0

Affected Versions ISC BIND 9 9.11.0
ISC BIND 9 9.18.0
ISC BIND 9 9.20.0
ISC BIND 9 9.21.0
ISC BIND 9 9.11.3-S1
ISC BIND 9 9.18.11-S1
ISC BIND 9 9.20.9-S1

CWE Classification

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

References

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    "lastseen": "",
    "description": "Multiple flaws have been identified in `named` related to the handling of DNS messages whose CLASS is not Internet (`IN`) \u2014 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 \u2014 recursion, dynamic updates (`UPDATE`), zone change notifications (`NOTIFY`), or processing of `IN`-specific record types in non-`IN` data \u2014 can cause assertion failures in `named`.\nThis 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.",
    "published": "2026-05-20T13:10:03.479Z",
    "modified": "2026-05-20T13:10:03.479Z",
    "type": "cve",
    "title": "Invalid handling of CLASS != IN",
    "source": "isc",
    "references": "https://kb.isc.org/docs/cve-2026-5946\nhttps://downloads.isc.org/isc/bind9/9.18.49\nhttps://downloads.isc.org/isc/bind9/9.20.23\nhttps://downloads.isc.org/isc/bind9/9.21.22",
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