# CVE-2020-13535: Privilege escalation in Kepware

> Attackers can overwrite service configuration to execute arbitrary code with SYSTEM privileges in Kepware LinkMaster.

- **Severity:** Critical 9.3 (`CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H`)
- **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:** 18 Dec 2020
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-mh9j-g4g3-6xcv

## What is CVE-2020-13535?

CVE-2020-13535 is a critical vulnerability in Kepware, published on 18 Dec 2020. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A privilege escalation vulnerability exists in Kepware LinkMaster 3.0.94.0. In its default configuration, an attacker can globally overwrite service configuration to execute arbitrary code with NT SYSTEM privileges.

Weakness: CWE-276 (Incorrect Default Permissions)

## Which versions are affected by CVE-2020-13535?

It affects 1 product.


Products: Kepware Linkmaster.

## How do I fix CVE-2020-13535?

No fix has been published for CVE-2020-13535 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-13535 being exploited?

There is no known exploitation of CVE-2020-13535 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-13535 and fix it if it is affected.

What it is: CVE-2020-13535 is a critical vulnerability in Kepware, published on 18 Dec 2020. 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-2020-13535 in the wild and no public exploit code.

Affected product: Kepware. 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-2020-13535/ (Markdown: https://insights.sbomify.com/CVE-2020-13535/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-13535
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-13535
- OSV: https://osv.dev/vulnerability/CVE-2020-13535

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-13535/
Summaries are generated and may contain mistakes; the official description above is the record.