CVE-2026-5946Invalid handling of CLASS != IN
Updated under an hour ago ()
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It affects ISC BIND 9 and 7 other products. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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
- 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Weakness (CWE)
- CWE-20, CWE-125, CWE-617, CWE-754, CWE-843, CWE-1287
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- isc
- NVD analysis
- Modified
- Record last updated
- Sep 17, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
ISC BIND 9 isc:bind_9 (from the name) | from 9.11.0 through 9.16.50; from 9.18.0 through 9.18.48; from 9.20.0 through 9.20.22; from 9.21.0 through 9.21.21; from 9.11.3-S1 through 9.16.50-S1; from 9.18.11-S1 through 9.18.48-S1; from 9.20.9-S1 through 9.20.22-S1 | CNA record |
Red Hat Red Hat Enterprise Linux 10 redhat:enterprise_linux | from 32:9.18.33-15.el10_2.2 not affected | CISA ADP |
from 32:9.11.4-26.P2.el7_9.21 not affected | CISA ADP | |
from 32:9.16.23-18.el9_4.12 not affected | CISA ADP | |
Red Hat Red Hat Enterprise Linux 9.6 Extended Update Support redhat:rhel_eus | from 32:9.16.23-31.el9_6.4 not affected | CISA ADP |
Red Hat Red Hat OpenShift Container Platform 4.16 redhat:openshift | from 416.94.202609011112-0 not affected | CISA ADP |
Red Hat Red Hat Hardened Images redhat:hummingbird | from 9.18.49-1.hum1 not affected | CISA ADP |
isc bind isc:bind | from 9.11.0 through 9.16.50; from 9.18.0 before 9.18.49; from 9.20.0 before 9.20.23; from 9.21.0 before 9.21.22 | NVD |
References
- https://kb.isc.org/docs/cve-2026-5946vendor-advisory
- https://downloads.isc.org/isc/bind9/9.18.49patch
- https://downloads.isc.org/isc/bind9/9.20.23patch
- https://downloads.isc.org/isc/bind9/9.21.22patch
- https://access.redhat.com/errata/RHSA-2026:20334
- https://access.redhat.com/errata/RHSA-2026:23360
- https://access.redhat.com/errata/RHSA-2026:24338
- https://access.redhat.com/errata/RHSA-2026:24339
- https://access.redhat.com/errata/RHSA-2026:24367
- https://access.redhat.com/errata/RHSA-2026:24368
- https://access.redhat.com/errata/RHSA-2026:55441
- https://access.redhat.com/errata/RHSA-2026:57189
- https://access.redhat.com/errata/RHSA-2026:60383
- https://access.redhat.com/errata/RHSA-2026:62549
- https://access.redhat.com/errata/RHSA-2026:65851
- https://access.redhat.com/security/cve/CVE-2026-5946
- https://bugzilla.redhat.com/show_bug.cgi?id=2479771
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-5946.json
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.