# LibreNMS — Stored XSS via SNMP/Syslog Data in Legacy Templates

Advisory record · `GHSA-7w8c-qgxg-m7jx`

- **Identifiers:** `GHSA-7w8c-qgxg-m7jx` · `CVE-2026-84192` · `PKSA-pcg8-3qh7-w8k9`
- **State:** Confirmed
- **Severity:** CVSS 7.1 High
- **Critical:** No
- **Weakness (CWE):** [CWE-79](https://cwe.mitre.org/data/definitions/79.html)
- **Tags:** [Cross-site scripting (XSS)](https://agentprime.io/advisories/tag/xss.md)
- **Published:** 26 Aug 2026
- **Updated:** 2 Sept 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 26 Aug 2026, 18:05 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `librenms/librenms` (Packagist): affected `<26.5.0`; fixed in `26.5.0`

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> LibreNMS versions before 26.5.0 contain a stored cross-site scripting flaw in several legacy PHP template files, where SNMP-sourced and syslog-sourced values (such as port descriptions and syslog program names) are output into HTML without escaping. An attacker who controls a monitored network device, through a compromised SNMP agent or a syslog sender, can inject JavaScript that runs in the browser of any authenticated LibreNMS user who views the affected pages. The fix is to upgrade librenms/librenms to version 26.5.0 or later.

Written 31 Oct 2026.

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 7.1 High, CVSS 4.0: `CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N`, from CNA (VulnCheck)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0033, the 26th percentile, on 15 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:06 UTC: First seen by agentprime
- 31 Oct 2026, 14:06 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-7w8c-qgxg-m7jx)

## Sources

- [GitHub Advisory Database: GHSA-7w8c-qgxg-m7jx](https://github.com/advisories/GHSA-7w8c-qgxg-m7jx)
- [OSV: GHSA-7w8c-qgxg-m7jx](https://osv.dev/vulnerability/GHSA-7w8c-qgxg-m7jx)
- <https://github.com/librenms/librenms/security/advisories/GHSA-7w8c-qgxg-m7jx>
- <https://github.com/librenms/librenms/pull/19660>
- <https://github.com/librenms/librenms/commit/6782af940c3c495755923b520a302f3a1cb1ce6b>
- <https://github.com/librenms/librenms>
- <https://github.com/librenms/librenms/releases/tag/26.5.0>
- <https://github.com/librenms/librenms/releases/tag/26.8.1>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-7w8c-qgxg-m7jx>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

---

The web page: <https://agentprime.io/advisories/GHSA-7w8c-qgxg-m7jx/>. Everything for agents: <https://agentprime.io/llms.txt>.