# CVE-2026-2728: LibreNMS: Cross-Site Scripting in ShowConfigController

> Authenticated attackers with admin privileges can inject scripts into the showconfig page, potentially compromising other users.

- **Severity:** Medium 4.6 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:A/VC:N/VI:L/VA:N/SC:N/SI:L/SA: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:** 13 Apr 2026
- **Updated:** 13 Apr 2026
- **Also known as:** GHSA-5gm9-622f-qcg5

## What is CVE-2026-2728?

CVE-2026-2728 is a medium-severity cross-site scripting vulnerability in Librenms Librenms, published on 13 Apr 2026. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.

### Official description

LibreNMS versions before 26.3.0 are affected by an authenticated Cross-site Scripting vulnerability on the showconfig page. Successful exploitation requires administrative privileges. Exploitation could result in XSS attacks being performed against other users with access to the page.

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

## Which versions are affected by CVE-2026-2728?

2 open source packages ship an affected version, including librenms/librenms. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `librenms/librenms` | Packagist | From 25.12.0 | 26.3.0 |
| `librenms/librenms` | Packagist | From 25.12.0 | 26.3.0 |

Products: Librenms Librenms.

## How do I fix CVE-2026-2728?

Upgrade librenms/librenms to 26.3.0 or later.

## Is CVE-2026-2728 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-2728 exists.

## Other vulnerabilities in Librenms Librenms

- [CVE-2023-4982](https://insights.sbomify.com/CVE-2023-4982/): Cross-site Scripting (XSS) - Stored in librenms/librenms (critical 9.8)
- [CVE-2022-29712](https://insights.sbomify.com/CVE-2022-29712/): Command injection in librenms (critical 9.8)
- [CVE-2021-44278](https://insights.sbomify.com/CVE-2021-44278/): Path traversal in librenms/librenms (critical 9.8)
- [CVE-2019-10665](https://insights.sbomify.com/CVE-2019-10665/): LibreNMS Information Disclosure (critical 9.8)
- [CVE-2018-20434](https://insights.sbomify.com/CVE-2018-20434/): LibreNMS arbitrary OS commands execution (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-2728 and fix it if it is affected.

What it is: CVE-2026-2728 is a medium-severity cross-site scripting vulnerability in Librenms Librenms, published on 13 Apr 2026. 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-2026-2728 exists.

Affected packages and fixed versions:
- librenms/librenms (Packagist): affected from 25.12.0; fixed in 26.3.0
- librenms/librenms (Packagist): affected from 25.12.0; fixed in 26.3.0

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-2026-2728/ (Markdown: https://insights.sbomify.com/CVE-2026-2728/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-2728
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-2728
- OSV: https://osv.dev/vulnerability/CVE-2026-2728

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-2728/
Summaries are generated and may contain mistakes; the official description above is the record.