# CVE-2020-5686: Auth bypass in UNIVERGE SV9500/SV8500 series

> An attacker can bypass authentication to access remote maintenance features and obtain sensitive information from NEC UNIVERGE PBX systems.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 13 Jan 2021
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-gq7j-hx55-h62p

## What is CVE-2020-5686?

CVE-2020-5686 is a high-severity authentication bypass vulnerability in NEC Corporation UNIVERGE SV9500/SV8500 series, published on 13 Jan 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Incorrect implementation of authentication algorithm issue in UNIVERGE SV9500 series from V1 to V7and SV8500 series from S6 to S8 allows an attacker to access the remote system maintenance feature and obtain the information by sending a specially crafted request to a specific URL.

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2020-5686?

It affects 2 products.


Products: Nec Univerge Sv8500 Firmware, Nec Univerge Sv9500 Firmware.

## How do I fix CVE-2020-5686?

No fix has been published for CVE-2020-5686 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-5686 being exploited?

There is no known exploitation of CVE-2020-5686 in the wild and no public exploit code.

## Other vulnerabilities in NEC Corporation UNIVERGE SV9500/SV8500 series

- [CVE-2020-5685](https://insights.sbomify.com/CVE-2020-5685/): Command injection in UNIVERGE SV9500/SV8500 series (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-5686 and fix it if it is affected.

What it is: CVE-2020-5686 is a high-severity authentication bypass vulnerability in NEC Corporation UNIVERGE SV9500/SV8500 series, published on 13 Jan 2021. 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-2020-5686 in the wild and no public exploit code.

Affected product: NEC Corporation UNIVERGE SV9500/SV8500 series. 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-2020-5686/ (Markdown: https://insights.sbomify.com/CVE-2020-5686/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-5686
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-5686
- OSV: https://osv.dev/vulnerability/CVE-2020-5686

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-5686/
Summaries are generated and may contain mistakes; the official description above is the record.