CVE-2024-36960 in Linux
Summary
by MITRE • 06/03/2024
In the Linux kernel, the following vulnerability has been resolved:
drm/vmwgfx: Fix invalid reads in fence signaled events
Correctly set the length of the drm_event to the size of the structure that's actually used.
The length of the drm_event was set to the parent structure instead of to the drm_vmw_event_fence which is supposed to be read. drm_read uses the length parameter to copy the event to the user space thus resuling in oob reads.
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Analysis
by VulDB Data Team • 04/02/2025
The vulnerability CVE-2024-36960 resides within the Linux kernel's graphics subsystem, specifically affecting the vmwgfx driver used for virtual machine graphics acceleration. This issue represents a classic buffer overflow condition that occurs during the handling of fence signaled events in the direct rendering manager framework. The flaw manifests when the kernel attempts to copy event data to user space, creating a scenario where invalid memory reads can occur due to improper length calculation. The vulnerability impacts systems utilizing VMware graphics drivers in virtualized environments where the drm_event structure is processed.
The technical root cause of this vulnerability stems from an incorrect assignment of the drm_event length field during the processing of fence signaled events. The kernel code erroneously sets the length parameter to match the size of the parent structure rather than the actual drm_vmw_event_fence structure that should be copied to user space. This misconfiguration causes the drm_read function to perform out-of-bounds reads when copying event data, as the copy operation uses the incorrectly specified length parameter. The vulnerability is classified as a buffer overflow condition that can result in information disclosure or potential privilege escalation depending on the execution context. According to CWE standards, this corresponds to CWE-121, which describes stack-based buffer overflow conditions, though the specific implementation involves heap-based memory handling in the kernel's event subsystem.
The operational impact of CVE-2024-36960 extends beyond simple memory corruption, potentially enabling attackers to extract sensitive information from kernel memory spaces or manipulate the graphics subsystem's behavior. Systems running affected kernel versions with VMware graphics drivers are at risk, particularly in virtualized environments where the vmwgfx driver is actively utilized. The vulnerability could be exploited by malicious processes to gain unauthorized access to kernel memory contents, potentially leading to privilege escalation or system compromise. Attackers could leverage this flaw to perform reconnaissance activities or establish persistent access within virtualized environments, making it particularly concerning for cloud infrastructure and virtual desktop environments. The issue aligns with ATT&CK technique T1068, which covers local privilege escalation through kernel vulnerabilities.
Mitigation strategies for CVE-2024-36960 primarily involve applying the latest kernel security patches that correct the length parameter assignment in the drm_event handling code. System administrators should prioritize updating their Linux kernel versions to include the fix that properly sets the drm_event length to match the actual drm_vmw_event_fence structure size. Additionally, implementing proper access controls and monitoring for unusual graphics driver behavior can help detect potential exploitation attempts. Organizations should also consider isolating systems with VMware graphics drivers in secure network zones and maintaining regular security assessments of their virtualization infrastructure to prevent unauthorized access to kernel-level resources. The vulnerability demonstrates the critical importance of proper memory management in kernel code and highlights the need for thorough testing of event handling mechanisms in graphics subsystems.