CVE-2026-13204

High

Description

If a provably insecure domain is covered by both an NSEC and NSEC3 record at the parent, and there exist an RRSIG for only one of these types, then BIND may exit unexpectedly with an assertion while validating this proof. This issue affects BIND 9 versions 9.11.0 through 9.18.50, 9.20.0 through 9.20.24, 9.21.0 through 9.21.23, 9.11.3-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.24-S1.

SeverityHigh

CVSS7.5

Exploit probability—

ProductIsc Bind

PublishedJul 22, 2026

First seenJul 22, 2026

Weakness typeCWE-617CWE-617

How to fix

Patches

Vendor advisories

kb.isc.org/docs/cve-2026-13204

Affected products

Product	Affected versions	Fixed in
isc bind	9.11.0 ≤ v ≤ 9.18.50, 9.11.3 ≤ v ≤ 9.18.50, 9.20.0 ≤ v ≤ 9.20.24, 9.20.9 ≤ v ≤ 9.20.24, 9.21.0 ≤ v ≤ 9.21.23	—

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