CVE-2026-55708: unbound — Fix

Description

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 local zones tree for an already configured named view when the view is configured with no local data to begin with. However, the creation through the control interface omits adding the default-protected zones (e.g., RFC 1918 reverse, AS112 zones, .onion, .localhost). Once the local zone tree exists without the defaults, every query for a default-protected name from a client mapped to that view escapes to the public DNS via the iterator instead of being answered locally, bypassing local policy expectations.

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CVSS v3.1 Score

3.1

LOW

CVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:U/C:L/I:L/A:N

EPSS — Exploit Prediction

0.0015

Probability of exploitation

0.05%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-1188 CWE-1188

Affected Products

Vendor	Product	Versions
nlnetlabs	unbound	1.6.0 — 1.25.2

References

Advisories & Patches

https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-55708.txt

Frequently Asked Questions

What is CVE-2026-55708? +

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 local zones tree for an already configured named view when the view is configured with no local data to begin with. However, the creation through the control interface omits adding the default-protected zones (e.g., RFC 1918 reverse, AS112 zones, .onion, .localhost). Once the local zone tree exists without the defaults, every query for a default-protected name from a client mapped to that view escapes to the public DNS via the iterator instead of being answered locally, bypassing local policy expectations. It has a CVSS v3.1 base score of 3.1 (LOW).

How severe is CVE-2026-55708? +

CVE-2026-55708 has a CVSS v3.1 score of 3.1 out of 10, rated LOW. This is a low-severity vulnerability with limited impact. The EPSS score is 0.0015, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-55708? +

CVE-2026-55708 affects products from nlnetlabs, specifically: unbound. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-55708? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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