High 7.4Published May 20, 2026

CVE-2026-3593Heap use-after-free vulnerability in BIND 9 DNS-over-HTTPS implementation

Updated under an hour ago (Oct 26, 2026, 4:30 PM ET)

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It affects ISC BIND 9 and 4 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

A use-after-free vulnerability exists within the DNS-over-HTTPS implementation. This issue affects BIND 9 versions 9.20.0 through 9.20.22, 9.21.0 through 9.21.21, and 9.20.9-S1 through 9.20.22-S1. BIND 9 versions 9.18.0 through 9.18.48 and 9.18.11-S1 through 9.18.48-S1 are NOT affected.

CVSS: 7.4 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:H
Weakness (CWE): CWE-416, CWE-825
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 1, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

ISC BIND 9 isc:bind_9 (from the name)	from 9.20.0 through 9.20.22; from 9.21.0 through 9.21.21; from 9.20.9-S1 through 9.20.22-S1; from 9.18.0 through 9.18.48 not affected; from 9.18.11-S1 through 9.18.48-S1 not affected	CNA record
Red Hat Red Hat Hardened Images redhat:hummingbird	from 9.18.48-1.1.hum1 not affected	CISA ADP
Red Hat Red Hat Enterprise Linux 10 redhat:enterprise_linux	10	CISA ADP
Red Hat Red Hat OpenShift Container Platform 4 redhat:openshift	4	CISA ADP
isc bind isc:bind	from 9.20.0 before 9.20.23; from 9.21.0 before 9.21.22	NVD

References

References

https://kb.isc.org/docs/cve-2026-3593	vendor-advisory
https://downloads.isc.org/isc/bind9/9.20.23	patch
https://downloads.isc.org/isc/bind9/9.21.22	patch
https://access.redhat.com/errata/RHSA-2026:7412
https://access.redhat.com/security/cve/CVE-2026-3593
https://bugzilla.redhat.com/show_bug.cgi?id=2479770
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-3593.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.