CVE-2022-48718 in Linux
Summary
by MITRE • 06/20/2024
In the Linux kernel, the following vulnerability has been resolved:
drm: mxsfb: Fix NULL pointer dereference
mxsfb should not ever dereference the NULL pointer which drm_atomic_get_new_bridge_state is allowed to return. Assume a fixed format instead.
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Analysis
by VulDB Data Team • 08/18/2025
The vulnerability identified as CVE-2022-48718 resides within the Linux kernel's display subsystem, specifically affecting the mxsfb driver component that manages framebuffer operations for i.MX SoC platforms. This issue represents a critical NULL pointer dereference flaw that could potentially lead to system instability or denial of service conditions. The vulnerability manifests when the mxsfb driver attempts to process display bridge state information through the drm_atomic_get_new_bridge_state function, which according to kernel documentation is permitted to return NULL values under certain operational conditions. The flaw occurs because the driver does not properly validate the return value from this function before attempting to dereference the pointer, creating an exploitable condition that could be leveraged by malicious actors to disrupt normal system operations.
The technical implementation of this vulnerability stems from improper error handling within the display driver's atomic commit processing logic. When the drm_atomic_get_new_bridge_state function is called during display configuration changes, it may legitimately return a NULL pointer to indicate that no new bridge state information is available or applicable. However, the mxsfb driver fails to account for this possibility and proceeds to dereference the returned pointer without validation. This pattern violates fundamental defensive programming practices and creates a direct path for system crashes when the driver encounters scenarios where the bridge state information is not present or cannot be properly retrieved. The vulnerability is classified as a NULL pointer dereference, which maps directly to CWE-476, representing a common class of programming errors that lead to system instability and potential privilege escalation vectors.
The operational impact of this vulnerability extends beyond simple system crashes, as it can affect embedded systems and devices that rely on the i.MX platform for display functionality. In production environments, this flaw could lead to unexpected system reboots, display corruption, or complete system lockups during display configuration changes. The vulnerability is particularly concerning in automotive, industrial, and embedded computing applications where display reliability is critical for system operation. Attackers could potentially exploit this condition to cause denial of service attacks against devices running affected kernel versions, disrupting display services and potentially affecting user experience or system functionality. The issue affects systems using the Freescale i.MX SoC family and related hardware platforms that implement the mxsfb driver for framebuffer operations, making it relevant to a broad range of embedded Linux deployments.
Mitigation strategies for CVE-2022-48718 should focus on implementing proper pointer validation and error handling within the affected driver code. System administrators and developers should ensure that all kernel updates are applied promptly, particularly those containing the fix for this vulnerability. The recommended approach involves adding explicit NULL checks before any pointer dereference operations, ensuring that the driver gracefully handles cases where drm_atomic_get_new_bridge_state returns NULL. This fix aligns with ATT&CK technique T1499.004, which covers system shutdown/reboot attacks, as the vulnerability could enable unauthorized system disruption. Additionally, implementing comprehensive testing procedures that simulate edge cases in display configuration changes can help identify similar issues in other driver components. Organizations should also consider implementing runtime monitoring to detect unusual system behavior that might indicate exploitation attempts, while maintaining current security patches to address any newly discovered vulnerabilities in the display subsystem.