# CVE-2023-28803: Traffic being bypassed by ZCC by configuring synthetic IP range as local network

> Attackers can bypass traffic inspection by spoofing synthetic IP addresses as local network ranges in Zscaler Client Connector on Windows.

- **Severity:** Medium 5.9 (`CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 23 Oct 2023
- **Updated:** 11 Sep 2024
- **Also known as:** GHSA-mwvw-6ggj-fhv5

## What is CVE-2023-28803?

CVE-2023-28803 is a medium-severity authentication bypass vulnerability in Zscaler Client Connector, published on 23 Oct 2023. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

An authentication bypass by spoofing of a device with a synthetic IP address is possible in Zscaler Client Connector on Windows, allowing a functionality bypass. This issue affects Client Connector: before 3.9.

Weakness: CWE-290 (Authentication Bypass by Spoofing)

## Which versions are affected by CVE-2023-28803?

It affects 1 product.


Products: Zscaler Client Connector.

## How do I fix CVE-2023-28803?

No fix has been published for CVE-2023-28803 yet. Limit exposure of the affected software until one is available.

## Is CVE-2023-28803 being exploited?

There is no known exploitation of CVE-2023-28803 in the wild and no public exploit code.

## Other vulnerabilities in Zscaler Client Connector

- [CVE-2020-11633](https://insights.sbomify.com/CVE-2020-11633/): Memory corruption in n/a (critical 9.8)
- [CVE-2024-23463](https://insights.sbomify.com/CVE-2024-23463/): Anti-Tampering bypass via Repair App functionality (high 8.8)
- [CVE-2023-28804](https://insights.sbomify.com/CVE-2023-28804/): Linux ZCC allows unsigned updates, allowing elevated Code Execution (high 8.2)
- [CVE-2023-28799](https://insights.sbomify.com/CVE-2023-28799/): Open redirect in Client Connector (high 8.2)
- [CVE-2023-28800](https://insights.sbomify.com/CVE-2023-28800/): Output encoding missing in redrurl parameter (high 8.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-28803 and fix it if it is affected.

What it is: CVE-2023-28803 is a medium-severity authentication bypass vulnerability in Zscaler Client Connector, published on 23 Oct 2023. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2023-28803 in the wild and no public exploit code.

Affected product: Zscaler Client Connector. 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-2023-28803/ (Markdown: https://insights.sbomify.com/CVE-2023-28803/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-28803
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-28803
- OSV: https://osv.dev/vulnerability/CVE-2023-28803

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-28803/
Summaries are generated and may contain mistakes; the official description above is the record.