CVE-2014-5263 in QEMU
Summary
by MITRE
vmstate_xhci_event in hw/usb/hcd-xhci.c in QEMU 1.6.0 does not terminate the list with the VMSTATE_END_OF_LIST macro, which allows attackers to cause a denial of service (out-of-bounds access, infinite loop, and memory corruption) and possibly gain privileges via unspecified vectors.
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Analysis
by VulDB Data Team • 03/28/2022
The vulnerability identified as CVE-2014-5263 resides within the QEMU virtual machine monitor version 1.6.0, specifically in the usb/hcd-xhci.c file where the vmstate_xhci_event function fails to properly terminate a list structure using the VMSTATE_END_OF_LIST macro. This flaw represents a classic software engineering error that can have severe consequences in virtualized environments where QEMU serves as a critical component for hardware emulation. The absence of proper list termination creates a dangerous condition where memory access patterns become unpredictable and potentially exploitable.
The technical nature of this vulnerability stems from improper memory management within the USB xHCI (eXtensible Host Controller Interface) controller emulation code. When the vmstate_xhci_event function processes virtual machine state information, it maintains a list of state elements that need to be serialized or deserialized during virtual machine operations. The missing VMSTATE_END_OF_LIST macro means that the list traversal mechanism cannot properly identify the end of the list structure, leading to potential out-of-bounds memory access patterns. This type of error commonly maps to CWE-129 Input Validation and Output Encoding, specifically related to improper handling of list termination conditions.
The operational impact of this vulnerability extends beyond simple denial of service scenarios to potentially enable privilege escalation attacks. Attackers can exploit this weakness by crafting malicious virtual machine state data that triggers the malformed list traversal, causing either infinite loops during state serialization, out-of-bounds memory accesses that could corrupt critical data structures, or memory corruption that might allow arbitrary code execution. The vulnerability affects QEMU versions up to 1.6.0 and represents a significant risk in environments where untrusted users can influence virtual machine state, particularly in cloud computing and multi-tenant virtualization platforms. This flaw aligns with ATT&CK technique T1059 Command and Scripting Interpreter and T1499 Endpoint Denial of Service, as it enables both denial of service and potential privilege escalation through improper state handling.
The mitigation strategy for CVE-2014-5263 involves updating to QEMU version 1.7.0 or later, where the fix properly implements the VMSTATE_END_OF_LIST macro termination. System administrators should also implement proper virtual machine state validation and sanitization procedures, particularly in multi-tenant environments where guest operating systems might be untrusted. Additionally, monitoring for unusual memory access patterns and implementing proper input validation for all virtual machine state data can help detect exploitation attempts. The vulnerability highlights the importance of rigorous code review processes for virtualization components and demonstrates how seemingly minor coding errors in state management can create serious security implications across virtualized infrastructure deployments.