CVE-2017-2584 in Linux
Summary
by MITRE
arch/x86/kvm/emulate.c in the Linux kernel through 4.9.3 allows local users to obtain sensitive information from kernel memory or cause a denial of service (use-after-free) via a crafted application that leverages instruction emulation for fxrstor, fxsave, sgdt, and sidt.
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Analysis
by VulDB Data Team • 05/13/2026
The vulnerability identified as CVE-2017-2584 resides within the Linux kernel's KVM (Kernel-based Virtual Machine) subsystem, specifically in the file arch/x86/kvm/emulate.c. This flaw affects kernel versions through 4.9.3 and represents a critical security issue that can be exploited by local attackers to gain unauthorized access to kernel memory or cause system instability. The vulnerability stems from improper handling of instruction emulation for specific x86 instructions including fxrstor, fxsave, sgdt, and sidt, which are fundamental components of processor instruction sets used for managing floating-point operations and system descriptor tables.
The technical root cause of this vulnerability lies in the kernel's virtualization subsystem's inadequate memory management during instruction emulation processes. When these specific instructions are executed within a virtualized environment, the KVM module fails to properly validate or sanitize the memory references, leading to potential information disclosure or use-after-free conditions. The flaw manifests when a malicious application crafted to exploit these instruction emulations can manipulate kernel memory structures, potentially exposing sensitive kernel data or triggering memory corruption that results in system crashes or denial of service conditions. This type of vulnerability falls under CWE-125, which describes out-of-bounds read conditions, and CWE-416, which covers use-after-free errors, both of which are common in kernel-level memory management failures.
The operational impact of CVE-2017-2584 extends beyond simple information disclosure, as it can be leveraged to create persistent security threats within virtualized environments. Attackers can exploit this vulnerability to extract confidential kernel data such as cryptographic keys, credentials, or other sensitive information stored in memory, potentially leading to privilege escalation or complete system compromise. The use-after-free condition can also be exploited to execute arbitrary code with kernel privileges, making this vulnerability particularly dangerous in multi-tenant virtualization environments where multiple users share the same physical hardware. According to ATT&CK framework category T1059, this vulnerability could be used for command and scripting interpreter techniques, while T1068 represents the privilege escalation potential that arises from kernel memory corruption. The vulnerability affects systems running Linux kernel versions up to 4.9.3, making it relevant to many enterprise environments that may still be using older kernel versions.
Mitigation strategies for CVE-2017-2584 primarily focus on kernel updates and virtualization security hardening. The most effective solution involves upgrading to Linux kernel version 4.9.4 or later, where the vulnerability has been patched through proper instruction emulation validation. Organizations should also implement virtualization security measures such as disabling unnecessary virtualization features, applying kernel lockdown mechanisms, and monitoring for suspicious instruction emulation patterns. System administrators should consider implementing additional security controls including kernel module signing, integrity checking mechanisms, and regular security audits of virtualized environments. The vulnerability's exploitation requires local access, but the potential for privilege escalation makes it a critical concern for system administrators managing virtualized infrastructure. Organizations running older kernel versions should prioritize immediate patching and consider implementing network segmentation to limit the potential impact of exploitation.