Security readout for executives and security teams
Plain-English summary
LibreNMS installations older than 26.8.0 may let an unauthenticated internet attacker bypass REST API login checks. Successful access could expose device credentials and administrative functions, potentially leading to remote code execution. Because LibreNMS manages network infrastructure, compromise could materially affect confidentiality, integrity, and operations.
Executive priority
Treat as an urgent remediation item. Prioritize internet-accessible and operationally critical LibreNMS systems, upgrade promptly, and investigate suspicious API activity. Network-management credentials and administrative control may be exposed if exploitation succeeds. Current sources do not establish active exploitation, so urgency is driven by impact and accessibility rather than confirmed attacks.
Technical view
The REST API accepts numeric token values where strings are expected. MySQL type coercion can cause these values to match stored token hashes, bypassing authentication. Protected API access may expose device credentials and administrative functionality; alert-template capabilities could then enable remote code execution. The issue is classified as CWE-287 with CVSS 4.0 score 9.2.
Likely exposure
Organizations running LibreNMS versions earlier than 26.8.0 are potentially affected, especially where the REST API is reachable from untrusted networks. Exposure depends on deployed version, API reachability, and surrounding access controls. The supplied evidence does not identify specific default configurations or quantify the installed vulnerable population.
Exploitation context
The vulnerability is remotely reachable, requires no privileges or user interaction, and has low attack complexity with an additional attack requirement reflected in the CVSS vector. The supplied bundle marks it absent from KEV and provides no evidence of active exploitation. Public technical advisories nevertheless make rapid defensive action appropriate.
Researcher notes
The central weakness is authentication type confusion between application token handling and MySQL comparison behavior. Reported impact chains protected API access to credential disclosure and administrative alert-template functionality capable of remote code execution. Confirm version boundaries and implementation details against the vendor advisory. No exploit prevalence, observed campaigns, or additional affected products are established by the supplied evidence.
Mitigation direction
- Upgrade LibreNMS to version 26.8.0 or later.
- Restrict REST API access to trusted networks until upgrading.
- Review vendor guidance for any additional remediation or configuration requirements.
- Rotate exposed credentials if investigation indicates unauthorized API access.
Validation and detection
- Inventory LibreNMS instances and record their exact installed versions.
- Confirm every instance runs version 26.8.0 or later.
- Identify whether REST API endpoints are reachable from untrusted networks.
- Review API and application logs for unexplained authentication or administrative activity.
- Verify credentials and alert-template configurations show no unauthorized changes.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-287: Credential and account abuse lookup
Authentication and credential weaknesses can make valid-account abuse and credential telemetry useful review starting points. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCredential and access behavior lookup
The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-86426 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Critical
- CVSS
- 9.2 (4.0)
- Known Exploited
- No
- Published
Vector: 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
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
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——VulnCheckVulnerability scoring details
Base CVSS 4.0 score
9.2CriticalVector: 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
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- GitHub Security Advisory (GHSA-cvq8-gqfq-3mvg)CVE reference, VulnCheck · vendor-advisory
- VulnCheck Advisory: LibreNMS before 26.8.0 Authentication Bypass via API Token Type ConfusionCVE reference, VulnCheck · third-party-advisory
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Authentication
Improper Authentication represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.