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CWE-290Weakness · CWE-290

CVE-2026-36537

CRITICAL · 9.8 CVSS v3.1 Published 2026-06-15
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
ThingsBoard v4.3.0.1 is vulnerable to an authentication bypass during the OAuth authorization code exchange. The application improperly trusts user-supplied identity data within the user parameter of the /login/oauth2/code/ endpoint. By manipulating the email address in this JSON object, a remote attacker can bypass authentication and gain full access to any existing user account on the platform without possessing the target user's credentials. This results in a complete account takeover.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

ThingsBoard v4.3.0.1 contains an authentication bypass in the OAuth2 authorization code exchange at /login/oauth2/code/. The application improperly trusts user-supplied identity data in the 'user' parameter, allowing attackers to manipulate the email address in the JSON object to impersonate any existing platform user and achieve full account takeover.

MitigationImplement strict server-side validation of OAuth authorization codes and verify that the returned identity claims match the expected values from the authorization server, rather than trusting client-supplied user data.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify ThingsBoard version
    Check the installed ThingsBoard version by reviewing the release notes, docker image tag, or the application startup logs. Common locations: check the Changelog file, pom.xml if source, or theAbout page in the ThingsBoard web UI.
    Affected if The installed version is 4.3.0.1 exactly, or falls within the v4.3.0.x release line where the vulnerability exists.
  2. Verify OAuth2 login is enabled
    Log in to ThingsBoard as an administrator and navigate to System Settings > OAuth2 Settings in the admin UI. Alternatively, inspect the thingsboard.yml configuration file for oauth2 configuration sections.
    Affected if OAuth2 authentication is enabled and configured with at least one OAuth2 provider.
  3. Inspect OAuth2 authorization code endpoint
    Review the ThingsBoard web server configuration or proxy logs for requests to endpoints matching /login/oauth2/code/. Check if the application processes the 'user' parameter directly from the authorization response.
    Affected if The application processes the authorization code exchange without strict server-side validation of identity claims from the OAuth provider.
  4. Check authentication flow implementation
    Review the ThingsBoard authentication handler code or configuration for the OAuth2 login flow. Look for logic that accepts user-supplied identity data (email, username) from the OAuth callback without independent verification from the authorization server.
    Affected if The OAuth2 implementation trusts client-supplied or callback-provided user identity data rather than extracting identity solely from the authorization server's verified token response.
  5. Review system logs for suspicious OAuth2 activity
    Search ThingsBoard logs for unusual /login/oauth2/code/ requests, particularly those with unexpected or changed email addresses, or account takeover indicators such as password changes immediately after OAuth login.
    Affected if There are OAuth2 login events where the email address does not match the expected identity from the OAuth provider, or unexpected account access patterns.

You are affected if running ThingsBoard v4.3.0.1 (or v4.3.0.x) with OAuth2 authentication enabled, where the OAuth2 authorization code exchange endpoint accepts and trusts user-supplied identity data without independent validation from the OAuth provider.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Implement strict server-side validation of OAuth authorization codes and verify that the returned identity claims match the expected values from the authorization server, rather than trusting client-supplied user data.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA3.0 h
21.0 hours of engineering $3,680
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-36537 in production — separate from our analysis above.

No notes yet

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What this is

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What belongs here
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