What is CVE-2026-26989?

CVE-2026-26989 is a medium-severity vulnerability in Librenms, classified under Cross-site Scripting. CVSS score: 4.3/10. Published 2026-02-20.

How severe is CVE-2026-26989?

Medium severity. CVSS v3 base score is 4.3 out of 10.

XSS in Librenms

CVE-2026-26989

LibreNMS is an auto-discovering PHP/MySQL/SNMP based network monitoring tool. Versions 25.12.0 and below are affected by a Stored Cross-Site Scripting (XSS) vulnerability in the Alert Rules workflow. An attacker with administrative privileges can inject malicious scripts that execute in the browser context of any user who accesses the Alert Rules page. This issue has been fixed in version 26.2.0.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2026-02-20 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:L/I:L/A:L.

EPSS exploit prediction

EPSS: 0.003 (25.3th percentile), scored 2026-10-03.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 25th percentile — 25.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001

Affected products

Librenms — versions < 26.2.0

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

github.com/librenms/librenms/security/advisories/GHSA-6xmx-xr9p-58p7 (Exploit, Third Party Advisory)
github.com/librenms/librenms/pull/19039 (Issue Tracking)
github.com/librenms/librenms/commit/087608cf9f851189847cb8e8e5ad002e59170c58 (Patch)
github.com/librenms/librenms/releases/tag/26.2.0 (Product, Release Notes)

Frequently asked questions

What is CVE-2026-26989?: CVE-2026-26989 is a medium-severity vulnerability in Librenms, classified under Cross-site Scripting. CVSS score: 4.3/10. Published 2026-02-20.
How severe is CVE-2026-26989?: Medium severity. CVSS v3 base score is 4.3 out of 10.