CVE-2026-11721

It is possible for an attacker's zone to respond to a query with an RRSIG that has a smaller number of labels than the zone in which the RRSIG is contained. This causes `named` to produce a wildcard name for a zone that is shorter than the attacker's zone, which can result in cache poisoning. For this attack to have any effect, the resolver under attack must have set `synth-from-dnssec yes;` (which is the default). 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.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact HIGH

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://downloads.isc.org/isc/bind9/9.20.26
https://downloads.isc.org/isc/bind9/9.21.24
https://kb.isc.org/docs/cve-2026-11721

Configurations

No configuration.

History

22 Jul 2026, 15:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-07-22 15:16

Updated : 2026-07-22 20:33

NVD link : CVE-2026-11721

Mitre link : CVE-2026-11721

CVE.ORG link : CVE-2026-11721

JSON object : View

Products Affected

No product.

CWE

CWE-1284

Improper Validation of Specified Quantity in Input

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