# CVE-2021-23881: Stored Cross Site Scripting in ENS

> An administrator can inject scripts into policy events that execute in a browser block page when triggered by a local user.

- **Severity:** Medium 4.8 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 10 Feb 2021
- **Updated:** 17 Sep 2024
- **Also known as:** GHSA-ffrc-37fw-2f8x

## What is CVE-2021-23881?

CVE-2021-23881 is a medium-severity cross-site scripting vulnerability in McAfee LLC Endpoint Security (ENS) for Windows, published on 10 Feb 2021. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.

### Official description

A stored cross site scripting vulnerability in ePO extension of McAfee Endpoint Security (ENS) prior to 10.7.0 February 2021 Update allows an ENS ePO administrator to add a script to a policy event which will trigger the script to be run through a browser block page when a local non-administrator user triggers the policy.

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

## Which versions are affected by CVE-2021-23881?

It affects 1 product.


Products: Mcafee Endpoint Security.

## How do I fix CVE-2021-23881?

No fix has been published for CVE-2021-23881 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-23881 being exploited?

There is no known exploitation of CVE-2021-23881 in the wild and no public exploit code.

## Other vulnerabilities in McAfee LLC Endpoint Security (ENS) for Windows

- [CVE-2020-7319](https://insights.sbomify.com/CVE-2020-7319/): Improper Access Control Vulnerability in ENS for Windows (high 8.8)
- [CVE-2020-7264](https://insights.sbomify.com/CVE-2020-7264/): Privilege Escalation vulnerability through symbolic links in ENS for Windows (high 8.8)
- [CVE-2020-7265](https://insights.sbomify.com/CVE-2020-7265/): Privilege Escalation vulnerability through symbolic links in ENSM (high 8.8)
- [CVE-2019-3582](https://insights.sbomify.com/CVE-2019-3582/): McAfee Endpoint Security updates fix a privilege escalation vulnerability (high 8.6)
- [CVE-2020-7257](https://insights.sbomify.com/CVE-2020-7257/): Privilege Escalation vulnerability through Symbolic links in ENS (high 8.4)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-23881 and fix it if it is affected.

What it is: CVE-2021-23881 is a medium-severity cross-site scripting vulnerability in McAfee LLC Endpoint Security (ENS) for Windows, published on 10 Feb 2021. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-23881 in the wild and no public exploit code.

Affected product: McAfee LLC Endpoint Security (ENS) 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-2021-23881/ (Markdown: https://insights.sbomify.com/CVE-2021-23881/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-23881
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-23881
- OSV: https://osv.dev/vulnerability/CVE-2021-23881

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-23881/
Summaries are generated and may contain mistakes; the official description above is the record.