CVE-2022-50878 in Linux
Summary
by MITRE • 12/30/2025
In the Linux kernel, the following vulnerability has been resolved:
gpu: lontium-lt9611: Fix NULL pointer dereference in lt9611_connector_init()
A NULL check for bridge->encoder shows that it may be NULL, but it already been dereferenced on all paths leading to the check. 812 if (!bridge->encoder) {
Dereference the pointer bridge->encoder. 810 drm_connector_attach_encoder(<9611->connector, bridge->encoder);
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Analysis
by VulDB Data Team • 04/26/2026
The vulnerability CVE-2022-50878 represents a critical NULL pointer dereference flaw within the Linux kernel's display driver subsystem, specifically affecting the Longtium LT9611 graphics bridge driver. This issue resides in the lt9611_connector_init() function where the kernel attempts to access bridge->encoder without proper validation, creating a potential system crash or denial of service condition. The flaw demonstrates a classic programming error where defensive coding practices have been insufficiently applied, allowing execution to proceed to a dereference operation before the null check occurs. This particular vulnerability falls under CWE-476 which specifically addresses NULL pointer dereference conditions in software implementations.
The technical implementation of this vulnerability occurs within the graphics driver's initialization sequence where the LT9611 bridge driver attempts to establish connector-encoder relationships for display output. The problematic code path shows that bridge->encoder is dereferenced on line 810 through the drm_connector_attach_encoder function call before the subsequent null check on line 812 occurs. This ordering issue creates a window where the system can attempt to access memory at a NULL address, potentially causing a kernel oops or system panic. The vulnerability affects systems utilizing the Longtium LT9611 graphics bridge hardware in embedded or automotive applications where kernel-level graphics functionality is critical.
From an operational impact perspective, this vulnerability presents significant risk to systems where the Linux kernel manages graphics output, particularly in automotive infotainment systems, industrial control devices, or embedded computing platforms that rely on the LT9611 bridge for display connectivity. The NULL pointer dereference can result in immediate system instability, requiring manual intervention or complete system reboot to restore functionality. Attackers could potentially exploit this vulnerability to cause denial of service conditions, particularly in environments where display output is critical for system operation or safety. The flaw represents a privilege escalation vector that could be leveraged by malicious actors to disrupt system services or potentially gain unauthorized access to system resources.
Mitigation strategies for CVE-2022-50878 involve applying the official kernel patch that reorders the conditional checks to ensure proper validation before dereference operations occur. System administrators should prioritize updating affected kernel versions to patched releases that address this specific NULL pointer dereference. The fix typically involves restructuring the code to perform the null check immediately before the dereference operation, preventing the execution path that leads to the invalid memory access. Organizations should also implement monitoring for system stability indicators and ensure comprehensive testing of graphics driver functionality after patch application. This vulnerability aligns with ATT&CK technique T1499.004 which covers network denial of service attacks, as the vulnerability can be exploited to cause system instability and service disruption in graphics-dependent environments.