CVE-2026-11721

CVE Details

Release Date:	2026-07-22
Impact:	Important	What is this?

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.

See more information about CVE-2026-11721 from MITRE CVE dictionary and NIST NVD

NOTE: The following CVSS metrics and score provided are preliminary and subject to review.

CVSS v3 metrics

Base Score:	7.5
Vector String:	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Version:	3.1
Attack Vector:	Network
Attack Complexity:	Low
Privileges Required:	None
User Interaction:	None
Scope:	Unchanged
Confidentiality Impact:	None
Integrity Impact:	High
Availability Impact:	None

Errata information

Platform	Errata	Release Date
Oracle Linux version 8 (bind)	ELSA-2026-54654	2026-08-13
Oracle Linux version 8 (bind9.16)	ELSA-2026-54509	2026-08-13
Oracle Linux version 9 (bind)	ELSA-2026-54510	2026-08-13