CVE-2026-55708 Privacy/configuration issue when adding local data in views through 'unbound-control'
Attackers can bypass local DNS policy protections for specific views by exploiting a flaw in unbound-control that omits default protected zones during local data addition.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-55708?
CVE-2026-55708 is a low-severity vulnerability in Nlnetlabs Unbound, published on 22 Jul 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
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.
Weakness: CWE-1188
Which versions are affected by CVE-2026-55708?
It affects 1 product.
Products include Nlnetlabs Unbound.
How do I fix CVE-2026-55708?
Apply the vendor's patch.
Is CVE-2026-55708 being exploited?
There is no known exploitation of CVE-2026-55708 in the wild and no public exploit code.
Other vulnerabilities in Nlnetlabs Unbound
- CVE-2026-81642 Heap buffer overflow and possible Remote Code Execution when digesting DNSKEY
- CVE-2026-33278 Possible arbitrary code execution during DNSSEC validation
- CVE-2026-42944 Heap overflow with multiple NSID, COOKIE, PADDING EDNS options
- CVE-2026-42959 Crash during DNSSEC validation of malicious content
- CVE-2026-82717 CNAME synthesis could lead to heap corruption
Sources
Also known as ALPINE-CVE-2026-55708, AZL-92934, DEBIAN-CVE-2026-55708, ECHO-2666-6303-c7a7, GHSA-c386-7qg7-h3qx, UBUNTU-CVE-2026-55708.