# CVE-2021-33850: Cross-site scripting in Microsoft Clarity

> Attackers can inject malicious scripts into Microsoft Clarity configuration pages, potentially executing code in victim browsers.

- **Severity:** Medium 5.4 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 19 Nov 2021
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-966j-fwrw-4gxw

## What is CVE-2021-33850?

CVE-2021-33850 is a medium-severity cross-site scripting vulnerability in Microsoft Clarity, published on 19 Nov 2021. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

There is a Cross-Site Scripting vulnerability in Microsoft Clarity version 0.3. The XSS payload executes whenever the user changes the clarity configuration in Microsoft Clarity version 0.3. The payload is stored on the configuring project Id page.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2021-33850?

It affects 1 product.


Products: Microsoft Clarity.

## How do I fix CVE-2021-33850?

No fix has been published for CVE-2021-33850 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-33850 being exploited?

There is no known exploitation of CVE-2021-33850 in the wild and no public exploit code.

## Other vulnerabilities in Microsoft Clarity

- [CVE-2024-0590](https://insights.sbomify.com/CVE-2024-0590/): Microsoft Clarity <= 0.9.3 - Cross-Site Request Forgery to Stored Cross-Site Scripting (medium 6.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-33850 and fix it if it is affected.

What it is: CVE-2021-33850 is a medium-severity cross-site scripting vulnerability in Microsoft Clarity, published on 19 Nov 2021. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-33850 in the wild and no public exploit code.

Affected product: Microsoft Clarity. 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-2021-33850/ (Markdown: https://insights.sbomify.com/CVE-2021-33850/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-33850
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-33850
- OSV: https://osv.dev/vulnerability/CVE-2021-33850

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-33850/
Summaries are generated and may contain mistakes; the official description above is the record.