CVE-2017-5573 in XenServer
Summary
by MITRE
An issue was discovered in Linux Foundation xapi in Citrix XenServer through 7.0. An authenticated read-only administrator can cancel tasks of other administrators.
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Analysis
by VulDB Data Team • 05/17/2026
The vulnerability identified as CVE-2017-5573 represents a critical access control flaw within the Citrix XenServer virtualization platform, specifically affecting versions through 7.0. This issue resides in the xapi component which serves as the core API for managing XenServer environments. The flaw allows authenticated users with read-only administrative privileges to perform unauthorized task cancellation operations against other administrators, effectively undermining the principle of least privilege and proper access segregation within virtualized environments.
The technical nature of this vulnerability stems from insufficient authorization checks within the xapi subsystem that manages administrative tasks and operations. When an authenticated user with read-only permissions attempts to cancel tasks, the system fails to properly validate whether the requesting user has adequate privileges to perform such operations on tasks owned by other administrators. This represents a classic privilege escalation scenario where a user with limited permissions can execute actions that should be restricted to higher-privileged users. The flaw operates at the application layer and affects the underlying task management mechanisms that govern administrative operations within the XenServer environment.
The operational impact of this vulnerability extends beyond simple unauthorized task cancellation, as it creates a potential vector for more serious security incidents. An attacker with read-only access could disrupt critical administrative operations, potentially causing service interruptions, data loss, or system instability. The vulnerability is particularly concerning in enterprise environments where XenServer is used for mission-critical applications, as it allows for the deliberate disruption of administrative activities by individuals who should not have such capabilities. This could lead to denial of service conditions, unauthorized system modifications, or the prevention of legitimate administrative tasks from completing successfully.
Mitigation strategies for CVE-2017-5573 should include immediate patching of affected XenServer installations to the latest available versions that address this specific authorization flaw. Organizations should also implement enhanced monitoring of administrative task cancellation activities to detect anomalous behavior patterns that might indicate exploitation attempts. Network segmentation and strict access controls should be enforced to limit the number of users with any administrative privileges, particularly those with read-only access that could potentially exploit this vulnerability. The implementation of role-based access controls and regular privilege reviews can help minimize the risk of unauthorized access to administrative functions. Additionally, organizations should consider implementing security information and event management solutions that can track and alert on suspicious administrative activities within their virtualized environments.
This vulnerability aligns with CWE-284 which describes improper access control issues, and represents a clear violation of the principle of least privilege. From an ATT&CK framework perspective, this flaw maps to privilege escalation techniques where adversaries with limited access can leverage system weaknesses to gain broader capabilities. The vulnerability demonstrates how insufficient authorization checks can create persistent security risks that remain exploitable across multiple environments and attack vectors. Organizations should treat this as a high-priority remediation item given its potential to enable broader compromise of virtualized infrastructure through unauthorized administrative actions.