Vulnerability · Published Jul 22, 2026 · Assigned by NLnet Labs
CVE-2026-55708Privacy/configuration issue when adding local data in views through 'unbound-control'
Low 3.1
In plain English
A low-severity security flaw in Unbound from NLnet Labs. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 5% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.22 | unbound | 1.25.2-r0 | ALPINE-CVE-2026-55708 |
| Alpine:v3.23 | unbound | 1.25.2-r0 | ALPINE-CVE-2026-55708 |
| Alpine:v3.24 | unbound | 1.25.2-r0 | ALPINE-CVE-2026-55708 |
| Debian:12 | unbound | no fix listed | DEBIAN-CVE-2026-55708 |
| Debian:13 | unbound | 1.26.1-0+deb13u1 | DEBIAN-CVE-2026-55708 |
| Debian:14 | unbound | 1.25.2-1 | DEBIAN-CVE-2026-55708 |
| Ubuntu:22.04:LTS | unbound | no fix listed | UBUNTU-CVE-2026-55708 |
| Ubuntu:24.04:LTS | unbound | no fix listed | UBUNTU-CVE-2026-55708 |
| Ubuntu:26.04:LTS | unbound | no fix listed | UBUNTU-CVE-2026-55708 |
| Ubuntu:26.10 | unbound | no fix listed | UBUNTU-CVE-2026-55708 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| NLnet Labs | Unbound | 1.6.0 – before 1.25.2 |
Weakness: CWE-1188 · Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:U/C:L/I:L/A:N
References
- https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-55708.txt vendor-advisory