CVE-2026-65642 in Plesk
Summary
by MITRE • 08/27/2026
Insecure direct object reference in Plesk 18.0.79.7 and earlier or 18.0.80 through 18.0.80.3, allows remote authenticated users to read and modify other customers' databases.
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Analysis
by VulDB Data Team • 08/27/2026
The vulnerability identified as an insecure direct object reference within Plesk versions 18.0.79.7 and earlier, as well as the specific range of 18.0.80 through 18.0.80.3, represents a critical failure in access control mechanisms that governs how user data is retrieved and manipulated by the application logic. This flaw stems from the server's reliance on client-supplied input to identify resources without performing adequate authorization checks against the identity of the authenticated user making the request. In typical web applications utilizing this pattern, an identifier such as a database ID or customer account number is passed directly in a URL parameter or API payload. The application assumes that because the user is authenticated, they are authorized to access any resource associated with that identifier. However, it fails to verify whether the requesting user actually owns or has permission to interact with the specific object being referenced. This architectural oversight allows an attacker who possesses valid credentials for one customer account on a shared Plesk hosting environment to enumerate and manipulate database identifiers belonging to other customers hosted on the same infrastructure.
From a technical perspective, this vulnerability aligns directly with CWE-639, which is classified as Insecure Direct Object Reference. The core issue lies in the lack of indirect object mapping or session-bound validation when processing requests related to database management operations. When an authenticated user submits a request containing a target identifier for a database operation, such as reading data from another customer's MySQL instance or modifying configuration settings, the backend service processes this instruction based solely on the provided ID rather than cross-referencing it with the current session's authorized scope. This absence of proper authorization logic effectively bypasses the multi-tenancy isolation that Plesk is designed to enforce between different hosting clients. The vulnerability does not require complex exploitation techniques; instead, it relies on simple parameter tampering or enumeration where an attacker iterates through sequential database IDs to discover and access resources belonging to other tenants.
The operational impact of this flaw is severe due to the sensitive nature of the data involved. Since Plesk serves as a control panel for web hosting management, successful exploitation allows remote authenticated users to read confidential information stored in databases owned by other customers. This can include personal identifiable information, financial records, proprietary business logic, and authentication credentials that may be reused across different services. Furthermore, the ability to modify these databases introduces risks of data integrity compromise, where an attacker could alter or delete critical data, leading to service disruption for legitimate users. In a shared hosting environment, this breach undermines the fundamental trust model between the hosting provider and its clients, potentially resulting in significant regulatory compliance violations such as GDPR or HIPAA breaches if sensitive personal health or financial data is exposed. The attack vector is classified under MITRE ATT&CK technique T1078, specifically Valid Accounts, as it leverages legitimate credentials to perform unauthorized actions within the application's functional scope.
Mitigation strategies must address both immediate remediation and long-term architectural improvements. For organizations running affected versions of Plesk, the primary recommendation is to apply vendor-provided security patches that update the control panel software to a version where this authorization check has been corrected. Administrators should verify their current build number against the advisory list to ensure they are not operating within the vulnerable ranges specified. In addition to patching, it is crucial to enforce strict input validation and implement robust access control checks at every layer of the application stack that handles object references. Developers must ensure that any request involving resource identifiers includes server-side verification confirming that the authenticated user has explicit permission for that specific resource before processing the action. Regular security audits focusing on authorization logic and penetration testing targeting IDOR vulnerabilities are also essential to detect similar flaws in custom scripts or third-party integrations managed through Plesk, thereby maintaining a strong defense-in-depth posture against data exfiltration and unauthorized modification attacks.