CVE-2024-53056 in Linux
Summary
by MITRE • 11/19/2024
In the Linux kernel, the following vulnerability has been resolved:
drm/mediatek: Fix potential NULL dereference in mtk_crtc_destroy()
In mtk_crtc_create(), if the call to mbox_request_channel() fails then we set the "mtk_crtc->cmdq_client.chan" pointer to NULL. In that situation, we do not call cmdq_pkt_create().
During the cleanup, we need to check if the "mtk_crtc->cmdq_client.chan" is NULL first before calling cmdq_pkt_destroy(). Calling cmdq_pkt_destroy() is unnecessary if we didn't call cmdq_pkt_create() and it will result in a NULL pointer dereference.
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Analysis
by VulDB Data Team • 12/07/2025
The vulnerability CVE-2024-53056 represents a critical NULL pointer dereference issue within the Linux kernel's display subsystem, specifically affecting the Mediatek display driver component. This flaw exists in the drm/mediatek driver module where the mtk_crtc_destroy() function fails to properly validate pointer states before executing cleanup operations. The vulnerability stems from improper error handling during the initialization phase of the command queue client, creating a scenario where cleanup routines attempt to operate on null references. The issue manifests when the mbox_request_channel() function fails during mtk_crtc_create(), leaving the cmdq_client.chan pointer in a NULL state while bypassing the cmdq_pkt_create() call that would normally establish valid command queue packet structures.
The technical implementation of this vulnerability involves a classic race condition and improper state management pattern within the driver's resource allocation and deallocation logic. When the mbox_request_channel() call fails, the system correctly sets mtk_crtc->cmdq_client.chan to NULL but fails to account for this state during subsequent cleanup operations. The absence of proper null checking before invoking cmdq_pkt_destroy() creates a direct path to NULL pointer dereference, which can lead to kernel panic or system instability. This type of vulnerability aligns with CWE-476, which specifically addresses NULL pointer dereference conditions, and represents a fundamental flaw in defensive programming practices within kernel space code where proper state validation is essential for preventing system crashes and potential privilege escalation.
The operational impact of this vulnerability extends beyond simple system crashes, as it can be exploited to cause denial of service attacks against systems running affected Linux kernels. In embedded systems or mobile devices that rely heavily on the Mediatek display controller, this vulnerability could result in complete system lockups, particularly during display initialization or configuration changes. The attack surface is primarily limited to systems utilizing Mediatek SoCs with display capabilities, but given the widespread adoption of these processors in various device categories, the potential impact remains significant. From an attacker's perspective, this vulnerability could be leveraged in privilege escalation scenarios where an unprivileged user or process could trigger the condition to cause system instability, making it particularly concerning for multi-user environments or systems with reduced privilege separation.
Mitigation strategies for CVE-2024-53056 require immediate kernel updates from vendors who have patched this specific issue, as the vulnerability cannot be effectively addressed through configuration changes or workarounds. System administrators should prioritize applying the relevant kernel patches that implement proper null pointer validation in the mtk_crtc_destroy() function before the next system reboot. The fix typically involves adding a conditional check to ensure that cmdq_pkt_destroy() is only called when cmdq_pkt_create() was previously successful, preventing the NULL pointer dereference scenario. Organizations should also implement monitoring for system stability indicators and ensure that their patch management processes include verification of kernel security updates. Additionally, the vulnerability highlights the importance of comprehensive testing for error paths in kernel drivers, particularly in resource management scenarios where multiple allocation functions may fail and require proper cleanup handling. The remediation process should include thorough regression testing to ensure that the fix does not introduce new stability issues or performance regressions in the display subsystem.