CVE-2014-0049 in Linux
Summary
by MITRE
Buffer overflow in the complete_emulated_mmio function in arch/x86/kvm/x86.c in the Linux kernel before 3.13.6 allows guest OS users to execute arbitrary code on the host OS by leveraging a loop that triggers an invalid memory copy affecting certain cancel_work_item data.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 05/07/2026
The vulnerability identified as CVE-2014-0049 represents a critical buffer overflow flaw within the Linux kernel's KVM (Kernel-based Virtual Machine) subsystem, specifically in the complete_emulated_mmio function located at arch/x86/kvm/x86.c. This issue affects Linux kernel versions prior to 3.13.6 and exposes systems running virtualized environments to potential host compromise. The vulnerability manifests when guest operating systems attempt to execute memory-mapped I/O operations that trigger an invalid memory copy operation, creating conditions where malicious input can overflow buffer boundaries and corrupt adjacent memory regions.
The technical implementation of this vulnerability leverages a loop structure within the emulated memory-mapped I/O handling code that processes cancel_work_item data structures. When a guest OS user executes specific memory operations, the function fails to properly validate input lengths or buffer boundaries, allowing an attacker to craft malicious input that exceeds the allocated buffer space. This buffer overflow creates a classic exploitation vector where arbitrary code execution becomes possible within the host operating system context, effectively breaking the isolation boundary between guest and host environments. The flaw operates at the hypervisor level, making it particularly dangerous as it can be exploited without requiring elevated privileges within the guest system itself.
The operational impact of CVE-2014-0049 extends beyond simple privilege escalation, as it fundamentally compromises the security model of virtualized environments. Attackers can leverage this vulnerability to execute arbitrary code on the host system with the privileges of the virtualization host process, potentially leading to complete system compromise. The vulnerability affects systems running Linux kernel versions up to 3.13.5, making it particularly relevant for enterprise environments that rely on older kernel versions for stability or compatibility reasons. Organizations using virtualized infrastructure, including cloud providers and data centers, face significant risk as this flaw can be exploited remotely through guest-to-host communication channels, potentially enabling attackers to pivot from compromised guest systems to underlying physical infrastructure.
Mitigation strategies for CVE-2014-0049 primarily focus on kernel version upgrades to 3.13.6 or later, which contain the necessary patches to address the buffer overflow condition. System administrators should also implement additional defensive measures including disabling unnecessary virtualization features, restricting guest OS capabilities, and monitoring for anomalous memory access patterns that might indicate exploitation attempts. The vulnerability aligns with CWE-121, which describes buffer overflow conditions in stack-based buffers, and can be categorized under ATT&CK technique T1055 for privilege escalation through kernel exploits. Organizations should also consider implementing hypervisor-level security controls such as KVM-specific security modules, memory integrity checking, and regular security assessments of virtualized environments to prevent exploitation of similar vulnerabilities in the future.