High 7.5Published Mar 25, 2026

CVE-2026-1519Excessive NSEC3 iterations cause high CPU load during insecure delegation validation

Updated under an hour ago (Oct 27, 2026, 9:40 AM ET)

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It affects ISC BIND 9 and 11 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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Every CVE for ISC BIND 9

Exploited in the last 30 days

If a BIND resolver is performing DNSSEC validation and encounters a maliciously crafted zone, the resolver may consume excessive CPU. Authoritative-only servers are generally unaffected, although there are circumstances where authoritative servers may make recursive queries (see: https://kb.isc.org/docs/why-does-my-authoritative-server-make-recursive-queries). This issue affects BIND 9 versions 9.11.0 through 9.16.50, 9.18.0 through 9.18.46, 9.20.0 through 9.20.20, 9.21.0 through 9.21.19, 9.11.3-S1 through 9.16.50-S1, 9.18.11-S1 through 9.18.46-S1, and 9.20.9-S1 through 9.20.20-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-606, CWE-770
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

Affected products

ISC BIND 9 isc:bind_9 (from the name)	from 9.11.0 through 9.16.50; from 9.18.0 through 9.18.46; from 9.20.0 through 9.20.20; from 9.21.0 through 9.21.19; from 9.11.3-S1 through 9.16.50-S1; from 9.18.11-S1 through 9.18.46-S1; from 9.20.9-S1 through 9.20.20-S1	CNA record
Red Hat Red Hat Enterprise Linux 10 redhat:enterprise_linux	from 32:9.18.33-10.el10_1.3 not affected	CISA ADP
Red Hat Red Hat Enterprise Linux 10.0 Extended Update Support redhat:enterprise_linux_eus	from 32:9.18.33-4.el10_0.3 not affected	CISA ADP
Red Hat Red Hat Enterprise Linux 6 Extended Lifecycle Support - EXTENSION redhat:rhel_els	from 32:9.8.2-0.68.rc1.el6_10.18 not affected	CISA ADP
Red Hat Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support redhat:rhel_aus	from 32:9.11.26-4.el8_4.9 not affected	CISA ADP
Red Hat Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On redhat:rhel_eus_long_life	from 32:9.11.26-4.el8_4.9 not affected	CISA ADP
Red Hat Red Hat Enterprise Linux 8.6 Telecommunications Update Service redhat:rhel_tus	from 32:9.11.36-3.el8_6.12 not affected	CISA ADP
Red Hat Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions redhat:rhel_e4s	from 32:9.11.36-3.el8_6.12 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_6.3 not affected	CISA ADP
Red Hat Red Hat OpenShift Container Platform 4.12 redhat:openshift	from 412.86.202606251120-0 not affected	CISA ADP
1–10 of 12

References

References

https://kb.isc.org/docs/cve-2026-1519	vendor-advisory
https://downloads.isc.org/isc/bind9/9.18.47	patch
https://downloads.isc.org/isc/bind9/9.20.21	patch
https://downloads.isc.org/isc/bind9/9.21.20	patch
https://lists.debian.org/debian-lts-announce/2026/04/msg00008.html	issue-tracking, third-party-advisory
https://access.redhat.com/errata/RHSA-2026:11371
https://access.redhat.com/errata/RHSA-2026:11372
https://access.redhat.com/errata/RHSA-2026:15890
https://access.redhat.com/errata/RHSA-2026:16060
https://access.redhat.com/errata/RHSA-2026:16064
1–10 of 25

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.