CVE-2022-48899 in Linux
Summary
by MITRE • 08/21/2024
In the Linux kernel, the following vulnerability has been resolved:
drm/virtio: Fix GEM handle creation UAF
Userspace can guess the handle value and try to race GEM object creation with handle close, resulting in a use-after-free if we dereference the object after dropping the handle's reference. For that reason, dropping the handle's reference must be done *after* we are done dereferencing the object.
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Analysis
by VulDB Data Team • 02/17/2026
The vulnerability identified as CVE-2022-48899 represents a critical use-after-free condition within the Linux kernel's drm/virtio subsystem that specifically affects Graphics Execution Manager (GEM) handle creation processes. This flaw exists in the virtual graphics device implementation that enables virtualized graphics acceleration through the virtio framework. The vulnerability stems from improper synchronization between handle creation and object reference management during concurrent operations, creating a race condition that can be exploited by malicious userspace processes to manipulate object lifecycles.
The technical implementation flaw occurs when userspace applications attempt to guess GEM handle values and simultaneously create new GEM objects while closing existing handle references. This race condition allows for a scenario where an object reference is dereferenced after the handle's reference count has been decremented, leading to a use-after-free condition. The vulnerability specifically impacts the order of operations within the GEM subsystem where reference management occurs before proper object dereferencing, creating a window where freed memory can be accessed and potentially manipulated. This issue falls under the CWE-416 vulnerability category, which specifically addresses use-after-free conditions in memory management operations.
The operational impact of this vulnerability extends beyond simple memory corruption, as it provides potential attack vectors for privilege escalation and system stability compromise within virtualized environments. Attackers can exploit this condition to execute arbitrary code within the kernel context, potentially leading to complete system compromise when running virtualized graphics workloads. The vulnerability affects systems utilizing virtio-gpu drivers in virtualized environments, including cloud computing platforms, containerized applications, and virtual desktop infrastructures where graphics acceleration is enabled. This represents a significant concern for security-conscious environments where virtualization is prevalent and kernel-level exploits could provide attackers with elevated privileges.
Mitigation strategies for CVE-2022-48899 require immediate patch application to affected kernel versions, as the fix involves reordering reference management operations to ensure handle references are dropped only after all object dereferencing operations are complete. System administrators should prioritize updating kernel versions to include the patched drm/virtio implementation that properly synchronizes these operations. Additionally, monitoring for unusual GEM handle creation patterns and implementing proper access controls for graphics virtualization components can help detect potential exploitation attempts. The fix aligns with ATT&CK technique T1068 by addressing privilege escalation vectors through kernel memory corruption, while also supporting defensive measures against process injection and code execution attacks that could leverage this vulnerability. Organizations should also consider implementing kernel module signing and integrity verification to prevent unauthorized modifications that could exacerbate the impact of such vulnerabilities in their virtualized infrastructure deployments.