CVE-2026-86426
CriticalPublic exploitLibreNMS 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.
Published Sep 7, 2026 · Updated Sep 20, 2026 · Also known as GHSA-cvq8-gqfq-3mvg
Key Facts
Patch immediately- CVE-2026-86426 is a critical-severity vulnerability (CVSS 9.2 v4) affecting Librenms.
- It is not listed in any known-exploited vulnerabilities catalog. Public exploit code is available.
- EPSS estimates a 3.9% probability of exploitation in the next 30 days.
- Fixed versions are available, including Librenms 26.8.0.
- Brandefense priority: patch immediately, because public exploit code exists for a high-severity flaw.
CVSS v4
9.2
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
EPSS (30-day exploit likelihood)
3.9%
Higher than 90.0% of all scored CVEs
Exploited in the wild
No known
Not in a known-exploited catalog
Public exploit code
Available
Proof-of-concept or weaponized module
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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.
Affected Products
2 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| LibrenmsLibrenms | See advisory | 26.8.0 |
Patched Releases
Librenms
26.8.0
Timeline
Publicly disclosed
Sep 7, 2026
Last updated
Sep 20, 2026
Weakness Type
- CWE-287 Improper Authentication
References
FAQ
Common Questions.
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.
Affected: Librenms. The full list is in the CVE brief.
It is not listed in any known-exploited vulnerabilities catalog.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
Public exploit code is available.
Fixed versions are available, including Librenms 26.8.0.
Brandefense priority: patch immediately, because public exploit code exists for a high-severity flaw.
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