No exploitation reportedFix available

CVE-2026-5946

Q: Is CVE-2026-5946 actively exploited?

Active exploitation of CVE-2026-5946 has not been confirmed. Its EPSS score was 1.8% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2026-5946?

CVE-2026-5946 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Invalid handling of CLASS != IN

No exploitation reported by the sources we read.

Published2026-05-20
Fixed in9.21.22 · 9.20.23 · 9.18.49
WeaknessCWE-125 · CWE-1287 · CWE-20

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC

2026-05-2013:16CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 15:37 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-5946?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-5946?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Isc bind

Branch	Affected	Fixed in	Source
9.21	≥ 9.21.0, < 9.21.22	9.21.22	NVD
9.20	≥ 9.20.0, < 9.20.23	9.20.23	NVD
9.18	≥ 9.18.0, < 9.18.49	9.18.49	NVD
9.x	≥ 9.11.0, ≤ 9.16.50	no fix published	NVD

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

bindAlmaLinux:10all versions · fixed in 32:9.18.33-15.el10_2.2and 7 other packages
bindAlmaLinux:9all versions · fixed in 32:9.16.23-40.el9_8.2and 9 other packages
bindAlmaLinux:8all versions · fixed in 32:9.11.36-16.el8_10.8and 16 other packages
bind9.16AlmaLinux:8all versions · fixed in 32:9.16.23-0.22.el8_10.6and 8 other packages
bind9.18AlmaLinux:9all versions · fixed in 32:9.18.29-14.el9_8.2and 6 other packages

Vendor advisories

CVE-2026-5946 Red Hat Product Security589 products fixed · 8 known affected
bind: BIND: Denial of Service via specially crafted DNS messages
bind as a component of Red Hat Enterprise Linux 6 · bind-chroot as a component of Red Hat Enterprise Linux 6 · bind-devel as a component of Red Hat Enterprise Linux 6 · +5 more
RHSA-2026:79160 Red Hat Product Security8 products fixed
Red Hat Security Advisory: bind9.16 security, bug fix, and enhancement update
RHSA-2026:70615 Red Hat Product Security4 products fixed
Red Hat Security Advisory: OpenShift Container Platform 4.18.56 bug fix and security update
RHSA-2026:70586 Red Hat Product Security4 products fixed
Red Hat Security Advisory: OpenShift Container Platform 4.17.58 bug fix and security update
RHSA-2026:65851 Red Hat Product Security4 products fixed
Red Hat Security Advisory: OpenShift Container Platform 4.18.55 bug fix and security update
RHSA-2026:62549 Red Hat Product Security4 products fixed
Red Hat Security Advisory: OpenShift Container Platform 4.16.70 bug fix and security update

9 more advisories

Full record on NVD

Fix

Update Isc bind to 9.21.22 · 9.20.23 · 9.18.49
Vendor fix Red Hat Product Security RHSA-2026:79160 · 8 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
Vendor fix Red Hat Product Security RHSA-2026:70615 · 4 productsFor OpenShift Container Platform 4.18 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this asynchronous errata update: https://docs.redhat.com/en/documentation/openshift_container_platform/4.…
Vendor fix Red Hat Product Security RHSA-2026:70586 · 4 productsFor OpenShift Container Platform 4.17 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this asynchronous errata update: https://docs.redhat.com/en/documentation/openshift_container_platform/4.…
Vendor fix Red Hat Product Security RHSA-2026:62549 · 4 productsFor OpenShift Container Platform 4.16 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this asynchronous errata update: https://docs.redhat.com/en/documentation/openshift_container_platform/4.…
Vendor fix Red Hat Product Security RHSA-2026:20334 · 15 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://images.redhat.com/
Workaround from the vendor Red Hat Product Security RHSA-2026:79160 · 36 productsMitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

Advisories and patches

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

NVDCVE recordread 2026-10-23
CISA-ADPSSVC decisionnone2026-05-20
OpenCVESSVC decisionnone—
CNACVSS 3.17.5read 2026-10-23
CNAweakness (CWE)CWE-125, CWE-1287, CWE-20, CWE-617, CWE-754, CWE-843read 2026-10-23
FIRST EPSSEPSS score1.8 %2026-10-22
OSVaffected packages—
Microsoft MSRCadvisory—

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published: 2026-05-20
Last Modified: 2026-09-17
NVD status: Modified
MSRC Title: Invalid handling of CLASS != IN

Frequently asked questions

What is CVE-2026-5946?

Is CVE-2026-5946 actively exploited?

Active exploitation of CVE-2026-5946 has not been confirmed. Its EPSS score was 1.8% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-5946?

CVE-2026-5946 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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