CVE-2026-12686
Summary
by MITRE • 07/06/2026
An authenticated user could manipulate a company ID parameter in a POST request to the backend to gain unauthorised access to other companies hosted within the same subdomain environment. The application does not adequately verify whether the requested company ID belongs to the authenticated user’s session, resulting in a cross-tenant authorisation bypass. If this vulnerability is successfully exploited, it allows unauthorised access to sensitive customer information, including billing data, and may enable the unauthorised modification of third-party data.
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Analysis
by VulDB Data Team • 07/06/2026
This vulnerability represents a critical authorization flaw that enables cross-tenant privilege escalation within a multi-tenant application environment. The issue stems from insufficient input validation and authorization checks when processing company ID parameters in POST requests. An authenticated user can manipulate the company ID parameter to access resources belonging to other tenants within the same subdomain, effectively bypassing the intended security boundaries that should separate customer data. This type of vulnerability commonly occurs in applications where tenant isolation is achieved through simple parameter-based identification rather than robust authorization mechanisms.
The technical implementation flaw manifests when the application accepts a company ID parameter without verifying that it corresponds to the authenticated user's legitimate tenant assignment. This weakness allows attackers to iterate through company IDs or use predictable patterns to access unauthorized data sets. The vulnerability operates at the application layer and can be exploited through session manipulation or direct API request tampering, making it particularly dangerous in cloud-based environments where multiple customers share infrastructure. According to cwe.org, this scenario aligns with CWE-285, which describes improper authorization within a security token context, and potentially CWE-287, covering issues related to authentication mechanisms.
The operational impact of this vulnerability extends beyond simple data exposure to encompass potential data manipulation and service disruption. Attackers can access sensitive billing information, customer records, and other proprietary data belonging to different tenants, creating significant compliance and privacy risks. The ability to modify third-party data introduces additional threats including data integrity compromise, which could lead to financial losses and regulatory penalties. Organizations using shared subdomain environments face heightened risk as the attack surface expands beyond individual tenant boundaries, potentially affecting multiple customers simultaneously.
Mitigation strategies should focus on implementing robust authorization controls that validate tenant ownership before granting access to resources. The application must enforce proper session management and ensure that all company ID parameters are validated against the authenticated user's legitimate tenant assignments. Implementing principle of least privilege access controls and using secure coding practices such as input sanitization and parameter validation can prevent unauthorized cross-tenant access. Security measures should include logging and monitoring for suspicious parameter manipulation attempts, as well as regular security testing to identify similar authorization bypass vulnerabilities. Organizations should also consider implementing additional authentication factors and establishing clear tenant isolation boundaries within their application architecture, aligning with defense-in-depth principles from the mitre ATT&CK framework's privilege escalation techniques.