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CVE-2026-86426

9.8, critical

librenms Improper Authentication Vulnerability

NVD (opens in a new tab) CVE.org (opens in a new tab)
CVSS
9.8, critical critical CVSS v3.1
EPSS, next 30 days
4% higher than 90% of scored CVEs
Exploitation
Exploit code published
Published
7 Sept 2026a month ago

Description

LibreNMS before 26.8.0 contains an authentication bypass vulnerability in the REST API that allows unauthenticated attackers to access protected endpoints by sending numeric values instead of string tokens. Attackers can exploit MySQL type coercion by sending small integers like 0 through 9 to match token hashes, gaining access to API functionality including device credentials and administrative features that enable remote code execution through alert templates.

Details

Vendor
Librenms
Product
librenms
Weakness
CWE-287 (opens in a new tab)
Status
Analyzed
Updated
18 Sept 2026
Assigner
disclosure@vulncheck.com

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References 2

Exploit code 1

Advisories 1

The kind is read from NVD's tags where present and from the shape of the URL otherwise, so treat it as a hint.

Other Librenms CVEs

Every Librenms CVE we hold

Same vendor in what we hold, not a known link between the flaws.

  • CVE-2026-109353 librenms SQL Injection Vulnerability EPSS 0.2% 7.1, high
  • CVE-2026-109357 LibreNMS before 26.9.0 contains an LDAP filter injection in ldap-authorization and ad-authorization modes because usernames are inserted… EPSS 0.5% 8.1, high

Beyond this page

Is CVE-2026-86426 in your network?

This page tells you how dangerous CVE-2026-86426 is out there. Whether it sits on one of your devices, only a scan of your own network can tell. That is what our systems do, every day, for the companies we protect.

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  • EXYS7950 KONDRA

    Detect it if it's exploited

    Until the patch is applied, Kondra monitors your network, events and endpoints in real time. It keeps an inventory of the software installed on every endpoint, and its anomaly detection rules flag what an attacker does once inside.

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Check your exposure

Assembled from the NVD 2.0 API, the CISA Known Exploited Vulnerabilities Catalog and FIRST EPSS. Scores are as of our last collection on 17 Oct 2026, not the live upstream state.