In NLnet Labs Unbound 1.6.0 up to and including 1.25.1, the 'view_local_data' and 'view_local_datas' commands of 'unbound-control' create a bare… (CVE-2026-55708)
Description
NLnet Labs Unbound versions 1.6.0 through 1.25.1 have a vulnerability in the 'view_local_data' and 'view_local_datas' commands of 'unbound-control'. These commands create a local zones tree for a named view without including default-protected zones such as RFC 1918 reverse, AS112 zones, .onion, and .localhost. As a result, queries for these default-protected names bypass local policy and are sent to the public DNS instead of being answered locally.
CVSS v3.1
Score 3.1low
Affected software
pkg:deb/ubuntu/unbound?arch=source&distro=esm-infra-legacy/trustypkg:deb/ubuntu/unbound?arch=source&distro=esm-infra-legacy/xenialpkg:deb/ubuntu/unbound?arch=source&distro=esm-infra/bionicpkg:deb/ubuntu/unbound?arch=source&distro=esm-infra/focalpkg:deb/ubuntu/unbound?arch=source&distro=jammypkg:deb/ubuntu/unbound?arch=source&distro=noblepkg:deb/ubuntu/unbound?arch=source&distro=stonkingpkg:deb/ubuntu/unbound?arch=source&distro=resoluteRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
In NLnet Labs Unbound versions 1.6.0 up to and including 1.25.1, the 'view_local_data' and 'view_local_datas' commands of the 'unbound-control' interface create a bare local zones tree for a named view configured without local data. However, this creation omits the addition of default-protected zones (e.g., RFC 1918 reverse zones, AS112 zones, .onion, .localhost). Consequently, when the local zone tree exists without these defaults, queries for default-protected names from clients mapped to that view are forwarded to the public DNS via the iterator, bypassing local DNS policy expectations.
Potential Impact
The vulnerability causes queries for default-protected DNS names to escape local resolution and be sent to the public DNS servers. This behavior bypasses local DNS policies intended to handle these names internally, potentially exposing internal network information or causing resolution failures. The CVSS score is 3.1 (medium severity), indicating limited impact primarily on confidentiality and integrity with no availability impact.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, avoid using the 'view_local_data' and 'view_local_datas' commands on views configured without local data or implement additional controls to prevent unintended DNS query leakage for default-protected zones.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- UBUNTU-CVE-2026-55708
- Osv Schema Version
- 1.7.0
- Ecosystems
- ["Ubuntu:Pro:14.04:LTS","Ubuntu:Pro:16.04:LTS","Ubuntu:Pro:18.04:LTS","Ubuntu:Pro:20.04:LTS","Ubuntu:22.04:LTS","Ubuntu:24.04:LTS","Ubuntu:26.10","Ubuntu:26.04:LTS"]
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6ad3f5ef2cdf04f65666350b
Added to database: 10/17/2026, 22:25:51 UTC
Last enriched: 10/18/2026, 00:44:33 UTC
Last updated: 10/18/2026, 00:44:33 UTC
Views: 2
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