CVE-2026-46582 Affecting unbound package, versions <1.25.2


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.19% (9th percentile)

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  • Snyk IDSNYK-ECHOLATEST-UNBOUND-18234983
  • published23 Jul 2026
  • disclosed22 Jul 2026

Introduced: 22 Jul 2026

NewCVE-2026-46582  (opens in a new tab)

How to fix?

Upgrade Echo:latest unbound to version 1.25.2 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream unbound package and not the unbound package as distributed by Echo. See How to fix? for Echo:latest relevant fixed versions and status.

In NLnet Labs Unbound 1.6.0 up to and including 1.25.1, a replay of a wildcard rrset as another piece of data, could be briefly considered DNSSEC secure based only on the RRSIG validation and stored into cache, before later validation treats it as bogus based on NSEC validation. When the resolving thread puts secure on the rrset, and another thread that is on the serve expired path then picks up the updated rrset contents with the secure status for a reply, it can be used to change a specific record, next to a wildcard that could be covered by the wildcard, into the wildcard. A malicious actor can exploit the possible poisonous effect by having any DNSSEC-singed domain (irrelevant to the victim domain) and a CNAME wrapper record that points to a record next to a wildcard (that could be covered by the wildcard). Then quering Unbound for the wildcard sibling record would seed the secure message. A later (after expiry) query for the CNAME wrapper would need to resolve the target sibling record. If the wildcard replay is injected into the response, the wildcard rrset will update the expired sibling record with a secure status before completing proper wildcard validation with NSEC records and eventually treating the CNAME wrapper answer as bogus. The updated poisoned rrset is now secure and points to the wildcard. This vulnerability is explicit for the serve expired path and needs injection of the signed wildcard rrset without the NSEC accompanying rrset.