Your RSA-2048 keys break in 2030. Find every one of them before attackers do.
🐘
🐘 Packagist
Not in CISA KEV
MEDIUM severity

CVE-2021-31274 — librenms

MEDIUMFix: librenms/librenms#12739

CVE-2021-31274 is a medium-severity (CVSS 5.4) Cross-site Scripting (XSS) vulnerability in librenms/librenms. A fix is available for librenms/librenms — see the affected versions and patch details below.

Cross-site Scripting in LibreNMS

Also known asGHSA-2r2w-jrh2-p4gr
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Oct 6, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
0.8%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs54th percentile — riskier than 54% of all scored CVEsHighest risk
0.00%0.43%0.85%1.28%0.0%0.8%Apr 26Aug 26Oct 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2021-31274 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,386 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected
🐘librenms/librenms

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

In LibreNMS < 21.3.0, a stored XSS vulnerability was identified in the API Access page due to insufficient sanitization of the $api->description variable. As a result, arbitrary Javascript code can get executed.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐘Packagistlibrenms/librenmsall versions21.3.0composer require librenms/librenms:^21.3.0

Affected Products

1 product · 1 configurations
Application
librenmslibrenms
< 21.3.0
range

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for librenms/librenms, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update librenms/librenms to 21.3.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-31274 is resolved across your whole dependency graph.

  3. Workarounds

    Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Frequently Asked Questions

In LibreNMS < 21.3.0, a stored XSS vulnerability was identified in the API Access page due to insufficient sanitization of the $api->description variable. As a result, arbitrary Javascript code can get executed.
O3 Security · Impact-Aware SCA

Is CVE-2021-31274 in your dependencies?

Find it across Packagist, including transitive dependencies.

Scan my dependencies How O3 SCA works
CVE-2021-31274: librenms XSS — Fixed in 21.3.0