CVE-2019-18390 in virglrenderer
Summary
by MITRE
An out-of-bounds read in the vrend_blit_need_swizzle function in vrend_renderer.c in virglrenderer through 0.8.0 allows guest OS users to cause a denial of service via VIRGL_CCMD_BLIT commands.
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Analysis
by VulDB Data Team • 03/16/2024
The vulnerability identified as CVE-2019-18390 represents a critical out-of-bounds read flaw within the virglrenderer library version 0.8.0 and earlier. This issue specifically manifests in the vrend_blit_need_swizzle function located in the vrend_renderer.c source file, creating a potential denial of service condition that can be exploited by unprivileged guest operating system users. The vulnerability occurs when processing VIRGL_CCMD_BLIT commands, which are fundamental operations used for image blitting and rendering in virtualized graphics environments. This flaw fundamentally undermines the stability of graphics rendering systems that rely on virglrenderer for virtualized GPU functionality.
The technical implementation of this vulnerability stems from inadequate bounds checking within the vrend_blit_need_swizzle function, where the code fails to validate input parameters before accessing memory locations. When guest operating systems submit VIRGL_CCMD_BLIT commands with malformed or excessive parameters, the function attempts to read data from memory addresses that fall outside the allocated buffer boundaries. This improper memory access pattern constitutes a classic out-of-bounds read vulnerability that can lead to system instability, application crashes, or complete system hangs. The flaw operates at the level of virtualized graphics command processing, making it particularly dangerous in virtualized environments where multiple guest operating systems share underlying hardware resources.
The operational impact of CVE-2019-18390 extends beyond simple denial of service conditions, as it can compromise the integrity of virtualized graphics environments and potentially enable more sophisticated attacks. In cloud computing and virtualization platforms, this vulnerability allows malicious guest users to disrupt services and potentially cause cascading failures across multiple virtual machines. The vulnerability affects systems using virglrenderer version 0.8.0 or earlier, which were widely deployed in virtualization solutions, container environments, and cloud infrastructure. Attackers can exploit this flaw by simply submitting specially crafted blit commands, requiring minimal privileges and technical expertise to trigger the out-of-bounds read condition.
Mitigation strategies for this vulnerability should prioritize immediate patching of affected virglrenderer installations to version 0.8.1 or later, which contains the necessary fixes for the bounds checking issue. System administrators should also implement monitoring and logging of graphics command processing to detect potential exploitation attempts. Network segmentation and privilege separation can help limit the impact of successful exploitation attempts. From a cybersecurity perspective, this vulnerability aligns with CWE-125, which specifically addresses out-of-bounds read conditions, and could potentially be leveraged as part of broader attack chains that might progress toward privilege escalation or lateral movement within virtualized environments. The ATT&CK framework would categorize this as a denial of service technique that could be used to weaken system defenses before more sophisticated attacks are attempted. Organizations should also consider implementing runtime protections and memory corruption detection mechanisms to provide additional layers of defense against similar vulnerabilities that may exist in graphics processing libraries.