CVE-2026-118685 in ToolJet
Summary
by MITRE • 10/28/2026
ToolJet from 3.20.2-lts before 3.20.242-lts contains an authorization bypass in SignupDisableGuard, which treats the string signup setting 'false' as truthy, so instance-level signup restrictions are not enforced. Unauthenticated attackers can send POST requests to /api/signup without an organizationId to create an account, join the default workspace, and receive a valid session.
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Analysis
by VulDB Data Team • 10/28/2026
The vulnerability identified in ToolJet versions prior to 3.20.242-lts represents a critical authorization bypass within the SignupDisableGuard middleware component. This flaw stems from a fundamental logic error in how the application interprets configuration settings related to user registration restrictions. Specifically, the system fails to correctly evaluate the boolean state of the signup disable flag when it is explicitly set to false via string input. In many programming environments and framework configurations, particularly those relying on loosely typed comparisons or specific parsing libraries, a non-empty string such as "false" can be erroneously evaluated as truthy rather than falsy. This misinterpretation causes the security guard responsible for enforcing instance-level signup restrictions to remain inactive, effectively disabling the intended access control mechanism that prevents unauthorized user creation.
From an operational perspective, this defect allows unauthenticated attackers to bypass registration controls entirely. By sending POST requests directly to the /api/signup endpoint without providing a required organizationId parameter, an attacker can successfully create new user accounts within the ToolJet instance. Upon successful account creation, the system automatically joins the newly created user to the default workspace and issues a valid authentication session token. This capability fundamentally undermines the security posture of any deployment where signup restrictions were intended to be enforced, whether for compliance reasons, resource management, or general access control policies. The ability to create accounts without organizational context also facilitates lateral movement within multi-tenant environments if such configurations are present, although the primary impact here is the unauthorized creation of privileged entry points into the application.
This vulnerability aligns with CWE-287, which describes Improper Authentication, and more specifically CWE-306, Missing Authentication for Critical Function, as the system fails to properly verify that a user should be allowed to perform the registration action based on configured security policies. In terms of the MITRE ATT&CK framework, this behavior is consistent with T1136.002, Internal Account Creation, where adversaries create accounts within an organization's systems for persistent access or privilege escalation. The lack of proper input validation and logical error in handling configuration states highlights a gap in secure coding practices regarding type coercion and security middleware implementation.
To mitigate this vulnerability, organizations running ToolJet must immediately upgrade to version 3.20.242-lts or later, where the logic for evaluating signup restriction settings has been corrected to properly interpret string representations of boolean values. Until an upgrade is feasible, administrators should consider implementing network-level controls such as web application firewalls that restrict access to the /api/signup endpoint based on IP reputation or known attack patterns. Additionally, reviewing and hardening instance configurations to ensure no unintended open registration paths exist can provide a layer of defense in depth. Regular security audits focusing on authentication middleware logic and configuration parsing are recommended to prevent similar logical flaws from being introduced in future updates.