# 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.

- **Severity:** Low 3.1 (`CVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:U/C:L/I:L/A:N`)
- **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:** Yes
- **Published:** 22 Jul 2026
- **Updated:** 22 Jul 2026
- **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

## 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 (Initialization of a Resource with an Insecure Default)

## Which versions are affected by CVE-2026-55708?

It affects 1 product.


Products: 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](https://insights.sbomify.com/CVE-2026-81642/): Heap buffer overflow and possible Remote Code Execution when digesting DNSKEY (critical 9.1)
- [CVE-2026-33278](https://insights.sbomify.com/CVE-2026-33278/): Possible arbitrary code execution during DNSSEC validation (critical 9.1)
- [CVE-2026-42944](https://insights.sbomify.com/CVE-2026-42944/): Heap overflow with multiple NSID, COOKIE, PADDING EDNS options (high 8.7)
- [CVE-2026-42959](https://insights.sbomify.com/CVE-2026-42959/): Crash during DNSSEC validation of malicious content (high 8.7)
- [CVE-2026-82717](https://insights.sbomify.com/CVE-2026-82717/): CNAME synthesis could lead to heap corruption (high 8.4)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-55708 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-55708 in the wild and no public exploit code.

Affected product: Nlnetlabs Unbound. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-55708/ (Markdown: https://insights.sbomify.com/CVE-2026-55708/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-55708
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-55708
- OSV: https://osv.dev/vulnerability/CVE-2026-55708

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-55708/
Summaries are generated and may contain mistakes; the official description above is the record.