CVE-2026-86426Public exploitNetwork attack vector

Unauthenticated API access via numeric token coercion

Published Sep 7, 2026 · Updated Sep 8, 2026

Authentication bypass in LibreNMS before 26.8.0 allows remote attackers to access protected REST API endpoints without a valid token. The ApiTokenGuard preserves the JSON type of api_token, and ApiToken::isValid compares an attacker-supplied integer with the text token_hash column, causing MySQL to coerce token hashes to small numbers. At least one enabled API token must exist; a match grants that token owner's API access, which can expose device credentials and, for an administrator token, enable code execution through alert templates.

CVSS severity9.2
Critical
EPSS probability1.41%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in LibreNMS before 26.8.0 allows remote attackers to access protected REST API endpoints without a valid token. The ApiTokenGuard preserves the JSON type of api_token, and ApiToken::isValid compares an attacker-supplied integer with the text token_hash column, causing MySQL to coerce token hashes to small numbers. At least one enabled API token must exist; a match grants that token owner's API access, which can expose device credentials and, for an administrator token, enable code execution through alert templates.

The record

CVE
CVE-2026-86426
Published
Sep 7, 2026
Updated
Sep 8, 2026
Vendor
LibreNMS
Product
LibreNMS
Classifications
CWE-287, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 7, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 8, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <26.8.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

LibreNMS · LibreNMSversion=0 <26.8.0

Published CVSS scores

9.2VulnCheckCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
9.8GitHub Security AdvisoryCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-287Improper Authentication
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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