CVE-2026-19668 PUBLISHED

Resource Exhaustion via Excessive DNSSEC Cryptographic Material Matching

Assigner: isc
Reserved: 12.08.2026 Published: 16.09.2026 Updated: 16.09.2026

A BIND recursive resolver may experience excessive resource consumption if it encounters large numbers of a particular kind of invalid DNSSEC record. Default limits on "max-records-per-type" and "max-types-per-name" help mitigate the exposure. This issue affects BIND 9 versions 9.11.0 through 9.18.50, 9.20.0 through 9.20.27, 9.21.0 through 9.21.25, 9.11.3-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.27-S1.

Metrics

CVSS 3.1

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CVSS Score: 5.3

Attack Vector	Network	Scope	Unchanged
Attack Complexity	Low	Confidentiality Impact	None
Privileges Required	None	Integrity Impact	None
User Interaction	None	Availability Impact	Low

CVSS 3.1

Product Status

Vendor	ISC
Product	BIND 9
Versions	Default: unaffected affected from 9.11.0 to 9.18.50 (incl.) affected from 9.20.0 to 9.20.27 (incl.) affected from 9.21.0 to 9.21.25 (incl.) affected from 9.11.3-S1 to 9.18.50-S1 (incl.) affected from 9.20.9-S1 to 9.20.27-S1 (incl.)

Exploits

We are not aware of any active exploits.

Workarounds

No workarounds known.

Solutions

Upgrade to the patched release most closely related to your current version of BIND 9: 9.20.29, 9.21.26, or 9.20.29-S1.

Credits

ISC would like to thank Zuyao Xu and Xiang Li of the All-in-One Security and Privacy Laboratory, Nankai University for bringing this vulnerability to our attention.