# CVE-2020-11635: Privilege escalation in Zscaler Client Connector for Windows

> A local attacker can execute code with system privileges or perform unauthorized actions due to insufficient RPC client validation in the Zscaler Client Connector.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/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:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 16 Feb 2021
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-6xqj-rg38-r6rr

## What is CVE-2020-11635?

CVE-2020-11635 is a high-severity vulnerability in Zscaler Client Connector for Windows, published on 16 Feb 2021. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

The Zscaler Client Connector prior to 3.1.0 did not sufficiently validate RPC clients, which allows a local adversary to execute code with system privileges or perform limited actions for which they did not have privileges.

## Which versions are affected by CVE-2020-11635?

It affects 1 product.


Products: Zscaler Client Connector.

## How do I fix CVE-2020-11635?

No fix has been published for CVE-2020-11635 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-11635 being exploited?

There is no known exploitation of CVE-2020-11635 in the wild and no public exploit code.

## Other vulnerabilities in Zscaler Client Connector for Windows

- [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-2020-11635 and fix it if it is affected.

What it is: CVE-2020-11635 is a high-severity vulnerability in Zscaler Client Connector for Windows, published on 16 Feb 2021. 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-2020-11635 in the wild and no public exploit code.

Affected product: Zscaler Client Connector for Windows. 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-2020-11635/ (Markdown: https://insights.sbomify.com/CVE-2020-11635/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-11635
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-11635
- OSV: https://osv.dev/vulnerability/CVE-2020-11635

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From sbomify Insights: https://insights.sbomify.com/CVE-2020-11635/
Summaries are generated and may contain mistakes; the official description above is the record.