CVE-2023-52795 in Linux
Summary
by MITRE • 05/21/2024
In the Linux kernel, the following vulnerability has been resolved:
vhost-vdpa: fix use after free in vhost_vdpa_probe()
The put_device() calls vhost_vdpa_release_dev() which calls ida_simple_remove() and frees "v". So this call to ida_simple_remove() is a use after free and a double free.
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Analysis
by VulDB Data Team • 01/11/2025
The vulnerability identified as CVE-2023-52795 represents a critical use-after-free condition within the Linux kernel's virtualization subsystem, specifically affecting the vhost-vdpa implementation. This flaw exists in the vhost_vdpa_probe() function where improper device reference management leads to memory corruption. The vulnerability stems from a fundamental error in how device resources are released and cleaned up during the virtual device initialization process, creating a scenario where memory that has already been freed is accessed, resulting in potential system instability and security risks. The issue manifests when the put_device() function is invoked, which subsequently calls vhost_vdpa_release_dev() and ultimately executes ida_simple_remove() on a structure that has already been deallocated, creating both use-after-free and double-free conditions.
The technical root cause of this vulnerability lies in the improper handling of device reference counting and memory management within the virtual device driver framework. When the vhost_vdpa_probe() function processes device initialization, it fails to properly manage the lifecycle of the device structure, leading to situations where the same memory location is freed twice or accessed after deallocation. This type of memory corruption vulnerability falls under CWE-416, which specifically addresses Use After Free conditions, and CWE-415, which covers Double Free scenarios. The vulnerability's impact is particularly severe in virtualized environments where vhost-vdpa is utilized for virtual device acceleration, as it can potentially be exploited to execute arbitrary code or cause denial of service conditions. The flaw demonstrates a classic improper resource management pattern where device cleanup functions are invoked without proper checks to ensure that resources have not already been released.
The operational impact of CVE-2023-52795 extends beyond simple system instability, potentially enabling attackers to leverage the use-after-free condition for privilege escalation or system compromise within virtualized environments. When exploited, this vulnerability can cause the kernel to crash or behave unpredictably, leading to denial of service across virtualized workloads that depend on vhost-vdpa functionality. The vulnerability affects systems running Linux kernel versions where the vhost-vdpa subsystem is active, particularly those utilizing virtualization technologies that rely on vhost-vdpa for device emulation. From an adversarial perspective, this flaw aligns with ATT&CK technique T1068, which covers the exploitation of local privileges through kernel vulnerabilities, and T1499, which addresses the exploitation of system resources for denial of service. The vulnerability's exploitation requires local access or a compromised guest environment in virtualized scenarios, making it particularly concerning for cloud environments and containerized deployments where virtualization security is paramount.
Mitigation strategies for CVE-2023-52795 should prioritize immediate kernel updates from vendors that include the patched version of the vhost-vdpa subsystem. Organizations must ensure their Linux kernel versions contain the fix that properly manages device reference counting and prevents the double-free scenario in vhost_vdpa_release_dev() function. System administrators should conduct thorough vulnerability assessments to identify systems running affected kernel versions and prioritize patch deployment across all virtualized environments. Additional defensive measures include implementing kernel hardening configurations such as enabling KASAN (Kernel Address Sanitizer) and KMSAN (Kernel Memory Sanitizer) to detect similar memory corruption patterns, though these may introduce performance overhead. Network segmentation and access controls should be maintained to limit potential exploitation vectors, while monitoring systems should be configured to detect unusual kernel behavior or memory corruption indicators that might signal exploitation attempts. The fix typically involves modifying the device cleanup sequence to ensure proper reference counting and prevent the execution of ida_simple_remove() on already-freed structures, thereby eliminating both the use-after-free and double-free conditions through proper resource lifecycle management.