# CVE-2026-35087: Authentication Bypass in Slican telephone exchanges

> Attackers can bypass administrative authentication on Slican telephone exchanges to gain unauthorized access and control.

- **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:** 27 May 2026
- **Updated:** 27 May 2026
- **Also known as:** GHSA-74x7-73gr-c646

## What is CVE-2026-35087?

CVE-2026-35087 is a critical authentication bypass vulnerability in Slican CCT-1668, published on 27 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Slican telephone exchanges allow administrative protocol authentication bypass. An attacker can bypass the need to enter login credentials by executing the appropriate command.

This issue was fixed in versions below:
- NCP: version 1.24.0250
- IPx series: version 6.61.0040
- CCT-1668: version 6.56.0430
- MAC-6400: version 6.56.0430
- CXS-0424: version 6.30.0510

The issue STILL EXISTS in End-Of-Life telephone exchanges in versions 4.xx and below:
- CCT-1668 (CCT1CPU)
- MAC-6400
- CXS-0424
These products were discontinued in 2011 and 2012 and and will not receive updates. These products require a hardware update in order to receive a software update. The vendor recommends that users of these devices contact the their service department directly to determine the options for upgrading.

Weakness: CWE-288 (Authentication Bypass Using an Alternate Path or Channel)

## Which versions are affected by CVE-2026-35087?


## How do I fix CVE-2026-35087?

No fix has been published for CVE-2026-35087 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-35087 being exploited?

There is no known exploitation of CVE-2026-35087 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-35087 and fix it if it is affected.

What it is: CVE-2026-35087 is a critical authentication bypass vulnerability in Slican CCT-1668, published on 27 May 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-2026-35087 in the wild and no public exploit code.

Affected product: Slican CCT-1668. 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-2026-35087/ (Markdown: https://insights.sbomify.com/CVE-2026-35087/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-35087
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-35087
- OSV: https://osv.dev/vulnerability/CVE-2026-35087

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-35087/
Summaries are generated and may contain mistakes; the official description above is the record.