# CVE-2026-3356: Missing Authentication for Critical Function vulnerability in Anritsu Remote Spectrum Monitor

> Unauthorized users can access and manipulate the management interface of Anritsu Remote Spectrum Monitors due to a lack of authentication mechanisms.

- **Severity:** Critical 9.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 31 Mar 2026
- **Updated:** 1 Apr 2026
- **Also known as:** GHSA-9c77-73hr-45rf

## What is CVE-2026-3356?

CVE-2026-3356 is a critical missing authorization vulnerability in Anritsu Remote Spectrum Monitor MS27100A, published on 31 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The MS27102A Remote Spectrum Monitor is vulnerable to an authentication bypass that allows unauthorized users to access and manipulate its management interface. Because the device provides no mechanism to enable or configure authentication, the issue is inherent to its design rather than a deployment error.

Weakness: CWE-306 (Missing Authentication for Critical Functionality)

## Which versions are affected by CVE-2026-3356?


## How do I fix CVE-2026-3356?

No fix has been published for CVE-2026-3356 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-3356 being exploited?

There is no known exploitation of CVE-2026-3356 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-3356 and fix it if it is affected.

What it is: CVE-2026-3356 is a critical missing authorization vulnerability in Anritsu Remote Spectrum Monitor MS27100A, published on 31 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-3356 in the wild and no public exploit code.

Affected product: Anritsu Remote Spectrum Monitor MS27100A. 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-2026-3356/ (Markdown: https://insights.sbomify.com/CVE-2026-3356/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-3356
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-3356
- OSV: https://osv.dev/vulnerability/CVE-2026-3356

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-3356/
Summaries are generated and may contain mistakes; the official description above is the record.