CVE-2026-44690

CVE Details

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

Description

In NLnet Labs Unbound 1.7.0 up to and including 1.25.1, insufficient validation of the RRSIG.Labels field combined with premature cache writes during RFC 8198 aggressive NSEC processing leads to cache poisoning that permits a malicious actor controlling a single delegated zone to poison arbitrary sibling zones under NSEC-signed parent domains. A malicious actor with one registered domain under an NSEC-signed TLD can serve malicious insecure DNS responses for unrelated sibling domains (sharing the same parent zone). Arbitrary delegations that do not exist under the parent domain and are covered by the parent's NSEC chain can be brought into insecure existence by fraudulent wildcard DS records (less labels than expected, unknown algorithm) from the malicious sibling domain. This allows the malicious actor to inject insecure wildcard records for those delegations.

See more information about CVE-2026-44690 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:	8.6
Vector String:	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N
Version:	3.1
Attack Vector:	Network
Attack Complexity:	Low
Privileges Required:	None
User Interaction:	None
Scope:	Changed
Confidentiality Impact:	None
Integrity Impact:	High
Availability Impact:	None

Errata information

Platform	Errata	Release Date
Oracle Linux version 10 (unbound)	ELSA-2026-55892	2026-08-17
Oracle Linux version 8 (unbound)	ELSA-2026-55784	2026-08-17
Oracle Linux version 9 (unbound)	ELSA-2026-55841	2026-08-17