# CVE-2018-16495: Auth bypass in Versa VOS

> Attackers can hijack user sessions by fixing session IDs before login, leading to account takeover in Versa VOS.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 26 May 2021
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-gvq8-8f97-wwvq

## What is CVE-2018-16495?

CVE-2018-16495 is a high-severity authentication bypass vulnerability in Versa VOS, published on 26 May 2021. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

In VOS user session identifier (authentication token) is issued to the browser prior to authentication but is not changed after the user successfully logs into the application. Failing to issue a new session ID following a successful login introduces the possibility for an attacker to set up a trap session on the device the victim is likely to login with.

Weakness: CWE-384 (Session Fixation)

## Which versions are affected by CVE-2018-16495?

It affects 1 product.


Products: Versa-Networks Versa Operating System.

## How do I fix CVE-2018-16495?

No fix has been published for CVE-2018-16495 yet. Limit exposure of the affected software until one is available.

## Is CVE-2018-16495 being exploited?

There is no known exploitation of CVE-2018-16495 in the wild and no public exploit code.

## Other vulnerabilities in Versa VOS

- [CVE-2018-16494](https://insights.sbomify.com/CVE-2018-16494/): Misconfiguration in Versa VOS (high 8.8)
- [CVE-2018-16499](https://insights.sbomify.com/CVE-2018-16499/): Weak cryptography in Versa VOS (medium 5.9)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-16495 and fix it if it is affected.

What it is: CVE-2018-16495 is a high-severity authentication bypass vulnerability in Versa VOS, published on 26 May 2021. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2018-16495 in the wild and no public exploit code.

Affected product: Versa VOS. 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-2018-16495/ (Markdown: https://insights.sbomify.com/CVE-2018-16495/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-16495
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-16495
- OSV: https://osv.dev/vulnerability/CVE-2018-16495

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-16495/
Summaries are generated and may contain mistakes; the official description above is the record.