A wildcard replay, as another piece of data, triggers poisoning in the serve expired reply path
Summary
| CVE | CVE-2026-46582 |
|---|---|
| State | PUBLISHED |
| Assigner | NLnet Labs |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-07-22 14:17:19 UTC |
| Updated | 2026-07-22 20:33:11 UTC |
| Description | 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. |
Risk And Classification
Primary CVSS: v3.1 3.7 LOW from [email protected]
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
Problem Types: CWE-358 | CWE-358 CWE-358: Improperly Implemented Security Check for Standard
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Secondary | 3.7 | LOW | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N |
| 3.1 | CNA | CVSS | 3.7 | LOW | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
HighPrivileges Required
NoneUser Interaction
NoneScope
UnchangedConfidentiality
NoneIntegrity
LowAvailability
NoneCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | NLnet Labs | Unbound | affected 1.6.0 1.25.2 semver | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| www.nlnetlabs.nl/downloads/unbound/CVE-2026-46582.txt | [email protected] | www.nlnetlabs.nl | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Qifan Zhang (Palo Alto Networks) (en)
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| CNA | 2026-05-16T00:00:00.000Z | Issue reported by Qifan Zhang |
| CNA | 2026-06-09T00:00:00.000Z | NLnet Labs shares patch |
| CNA | 2026-06-13T00:00:00.000Z | Qifan Zhang verifies patch |
| CNA | 2026-07-22T00:00:00.000Z | Fixes released with version 1.25.2 |
Solutions
CNA: This issue is fixed starting with version 1.25.2
There are currently no legacy QID mappings associated with this CVE.