# CVE-2021-25933: Cross-site Scripting in OpenNMS Horizon

> An authenticated attacker can inject malicious scripts via group parameters, potentially compromising admin accounts and systems in OpenNMS.

- **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:** Yes
- **Published:** 20 May 2021
- **Updated:** 30 Apr 2025
- **Also known as:** GHSA-jjhw-5mxp-2g2q

## What is CVE-2021-25933?

CVE-2021-25933 is a medium-severity cross-site scripting vulnerability in OpenNMS, published on 20 May 2021. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.

### Official description

In OpenNMS Horizon, versions opennms-1-0-stable through opennms-27.1.0-1; OpenNMS Meridian, versions meridian-foundation-2015.1.0-1 through meridian-foundation-2019.1.18-1; meridian-foundation-2020.1.0-1 through meridian-foundation-2020.1.6-1 are vulnerable to Stored Cross-Site Scripting, since the function `validateFormInput()` performs improper validation checks on the input sent to the `groupName` and `groupComment` parameters. Due to this flaw, an authenticated attacker could inject arbitrary script and trick other admin users into downloading malicious files which can cause severe damage to the organization using opennms.

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

## Which versions are affected by CVE-2021-25933?

2 open source packages ship an affected version, including org.opennms:opennms. It affects 2 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `org.opennms:opennms` | Maven | From 1.0.0 | 27.1.1 |
| `org.opennms:opennms` | Maven | From 1.0.0 | 27.1.1 |

Products: Opennms Horizon, Opennms Meridian.

## How do I fix CVE-2021-25933?

Upgrade org.opennms:opennms to 27.1.1 or later.

## Is CVE-2021-25933 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-25933 exists.

## Other vulnerabilities in OpenNMS

- [CVE-2021-25931](https://insights.sbomify.com/CVE-2021-25931/): Cross-Site Request Forgery in OpenNMS Horizon (high 8.8)
- [CVE-2021-3396](https://insights.sbomify.com/CVE-2021-3396/): OpenNMS Horizon RCE via JEXL2 expression (high 8.8)
- [CVE-2023-0872](https://insights.sbomify.com/CVE-2023-0872/): ROLE_REST can be used to escalate to ROLE_ADMIN via /rest/users (high 8.2)
- [CVE-2023-0870](https://insights.sbomify.com/CVE-2023-0870/): Form Can Be Manipulated with Cross-Site Request Forgery (CSRF) (high 8.1)
- [CVE-2020-11886](https://insights.sbomify.com/CVE-2020-11886/): SQL injection in n/a (high 8.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-25933 and fix it if it is affected.

What it is: CVE-2021-25933 is a medium-severity cross-site scripting vulnerability in OpenNMS, published on 20 May 2021. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-25933 exists.

Affected packages and fixed versions:
- org.opennms:opennms (Maven): affected from 1.0.0; fixed in 27.1.1
- org.opennms:opennms (Maven): affected from 1.0.0; fixed in 27.1.1

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-2021-25933/ (Markdown: https://insights.sbomify.com/CVE-2021-25933/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-25933
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-25933
- OSV: https://osv.dev/vulnerability/CVE-2021-25933

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-25933/
Summaries are generated and may contain mistakes; the official description above is the record.