CVE-2026-11721

Published: Jul 22, 2026Modified: Oct 24, 2026

7.5

Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Exploitability: 3.9 / Impact: 3.6

Source: security-officer@isc.org (Secondary)

Description

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.

Related CWEs

CWE-1284

Improper Validation of Specified Quantity in Input

The product receives input that is expected to specify a quantity (such as size or length), but it does not validate or incorrectly validates that the quantity has the required properties.

References (3)

https://downloads.isc.org/isc/bind9/9.20.26

Source: security-officer@isc.org

https://downloads.isc.org/isc/bind9/9.21.24

Source: security-officer@isc.org

https://kb.isc.org/docs/cve-2026-11721

Source: security-officer@isc.org

Timeline

No history available yet.