CVE-2014-1893 in Xen
Summary
by MITRE
Multiple integer overflows in the (1) FLASK_GETBOOL and (2) FLASK_SETBOOL suboperations in the flask hypercall in Xen 4.1.x, 3.3.x, 3.2.x, and earlier, when XSM is enabled, allow local users to cause a denial of service (processor fault) via unspecified vectors, a different vulnerability than CVE-2014-1891, CVE-2014-1892, and CVE-2014-1894.
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Analysis
by VulDB Data Team • 05/09/2026
The vulnerability identified as CVE-2014-1893 represents a critical security flaw within the Xen hypervisor's security module, specifically affecting versions 4.1.x, 3.3.x, and 3.2.x where the eXtensible Security Module (XSM) is enabled. This issue manifests as integer overflows within two distinct suboperations of the flask hypercall interface, namely FLASK_GETBOOL and FLASK_SETBOOL, which are fundamental components of Xen's access control mechanisms. The flaw resides in the handling of integer values during these security-related operations, where insufficient bounds checking allows malicious input to cause arithmetic overflow conditions that can corrupt system state and potentially lead to system instability.
The technical nature of this vulnerability falls under CWE-190, which specifically addresses integer overflow conditions, and more broadly relates to CWE-129, which covers insufficient validation of array indices. These integer overflows occur when the hypervisor processes user-supplied parameters within the flask hypercall interface without proper validation of input ranges, allowing attackers to manipulate integer values beyond their intended maximum limits. The exploitation mechanism leverages the fact that these operations are accessible to local users within the virtualized environment, making them particularly dangerous as they can be triggered from within guest operating systems or privileged user contexts.
From an operational impact perspective, this vulnerability creates a significant denial of service condition that can result in processor faults and system crashes, effectively compromising the stability and availability of virtualized environments. The vulnerability is particularly concerning because it operates at the hypervisor level, meaning that successful exploitation could potentially allow local users to disrupt the entire virtualization infrastructure rather than just individual virtual machines. The impact extends beyond simple service disruption as these processor faults can lead to complete system hangs or unexpected reboots, creating cascading failures in multi-tenant cloud environments where multiple virtual machines share the same physical host.
The attack surface for this vulnerability is limited to systems running affected Xen versions with XSM enabled, making it particularly relevant for cloud providers, hosting environments, and organizations utilizing virtualization technologies where local privilege escalation is possible. The vulnerability is distinct from related CVEs CVE-2014-1891, CVE-2014-1892, and CVE-2014-1894, indicating that while they all relate to Xen's security module, each addresses different aspects of the flask hypercall interface. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and denial of service, specifically T1068 (Local Privilege Escalation) and T1499 (Endpoint Denial of Service), as it allows local users to cause system-level failures through manipulation of hypervisor interfaces.
Mitigation strategies for CVE-2014-1893 primarily involve upgrading to patched versions of the Xen hypervisor, specifically versions that address the integer overflow conditions in the flask hypercall interface. Organizations should also consider implementing additional security controls such as restricting access to hypervisor interfaces, monitoring for unusual system behavior, and ensuring that XSM is properly configured with appropriate security policies. The vulnerability highlights the importance of thorough input validation in hypervisor code and demonstrates why security patches for core virtualization components must be prioritized in enterprise security maintenance programs. System administrators should also consider implementing runtime monitoring solutions that can detect and alert on anomalous behavior patterns that might indicate exploitation attempts.