CVE-2026-11622

High

Description

A DNSSEC validating resolver that is under a random subdomain attack against a DNSSEC-signed zone can suffer from runaway memory usage. The attacker needs to be able to send queries faster than the resolver can perform validation. The increased memory usage can be orders of magnitude beyond the limit configured in the `max-cache-size` parameter. 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-770Allocation of resources without limits

How to fix

Patches

Vendor advisories

kb.isc.org/docs/cve-2026-11622

Affected products

Product	Affected versions	Fixed in
isc bind	9.11.3 ≤ v ≤ 9.18.50, 9.18.0 ≤ 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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