CVE-2023-1513 in Linux
Summary
by MITRE • 03/23/2023
A flaw was found in KVM. When calling the KVM_GET_DEBUGREGS ioctl, on 32-bit systems, there might be some uninitialized portions of the kvm_debugregs structure that could be copied to userspace, causing an information leak.
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Analysis
by VulDB Data Team • 08/11/2025
The vulnerability identified as CVE-2023-1513 resides within the Kernel-based Virtual Machine (KVM) subsystem of Linux kernel virtualization infrastructure. This issue specifically manifests when the KVM_GET_DEBUGREGS ioctl command is invoked on 32-bit architectural systems, creating a scenario where sensitive uninitialized memory contents may be inadvertently exposed to user-space applications. The flaw represents a classic information disclosure vulnerability that undermines the security boundaries between kernel and user space components.
The technical root cause of this vulnerability stems from improper initialization of the kvm_debugregs structure within the KVM implementation. When the ioctl interface processes the KVM_GET_DEBUGREGS request on 32-bit systems, certain fields within the structure remain uninitialized, creating potential leakage of kernel memory contents including sensitive data, cryptographic keys, or system state information. This occurs because the kernel fails to properly zero out or initialize all members of the structure before copying it to user space, creating a pathway for information leakage that violates fundamental security principles of memory isolation.
The operational impact of CVE-2023-1513 extends beyond simple information disclosure, as it can potentially expose critical system information that adversaries might leverage for further exploitation. On 32-bit systems running KVM virtualization environments, any process with access to the KVM device interface can potentially invoke this ioctl call and receive uninitialized memory contents, which could include remnants of previous kernel operations, sensitive configuration data, or other confidential information stored in memory. This vulnerability affects virtualization environments where 32-bit guests are utilized, particularly impacting cloud computing platforms and server virtualization deployments that rely on KVM for hypervisor functionality.
This vulnerability maps to CWE-248, an information exposure weakness, and aligns with ATT&CK technique T1005 which covers data from local system. The flaw demonstrates a failure in proper memory management and initialization practices within the kernel's virtualization subsystem, creating an attack surface that could be exploited by malicious actors with access to the KVM device interface. The vulnerability is particularly concerning in multi-tenant environments where proper isolation between virtual machines is essential for maintaining security boundaries. Organizations utilizing KVM-based virtualization on 32-bit architectures should prioritize patching this vulnerability to prevent potential exploitation that could lead to privilege escalation or additional security breaches.
Mitigation strategies for CVE-2023-1513 involve applying the latest kernel patches that properly initialize the kvm_debugregs structure before exposing it to user space. System administrators should ensure that all virtualization hosts running KVM are updated to versions that address this specific initialization flaw. Additionally, monitoring for unauthorized access to KVM device interfaces and implementing proper access controls can help reduce the attack surface. Organizations should also consider migrating away from 32-bit virtualization environments where possible, as 64-bit architectures typically provide better memory management and security controls. The vulnerability highlights the importance of proper memory initialization in kernel code and serves as a reminder of the critical security implications that can arise from seemingly minor implementation oversights in virtualization infrastructure components.