CVE-2023-54018 in Linux
Summary
by MITRE • 12/24/2025
In the Linux kernel, the following vulnerability has been resolved:
drm/msm/hdmi: Add missing check for alloc_ordered_workqueue
Add check for the return value of alloc_ordered_workqueue as it may return NULL pointer and cause NULL pointer dereference in `hdmi_hdcp.c` and `hdmi_hpd.c`.
Patchwork: https://patchwork.freedesktop.org/patch/517211/
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 12/26/2025
The vulnerability identified as CVE-2023-54018 resides within the Linux kernel's display subsystem, specifically affecting the msm hdmi driver component. This issue demonstrates a critical flaw in error handling mechanisms that can lead to system instability and potential security implications. The vulnerability manifests in the drm/msm/hdmi subsystem where proper validation of resource allocation is absent, creating a scenario where a null pointer dereference can occur during hdmi hdcp and hdmi hpd operations. The affected code path involves workqueue allocation functions that may return null pointers under certain conditions, yet the subsequent code does not properly validate these return values before proceeding with operations that assume valid allocation.
The technical root cause of this vulnerability stems from inadequate error checking in the alloc_ordered_workqueue function call within the hdmi driver implementation. When alloc_ordered_workqueue fails to allocate the requested workqueue structure, it returns a null pointer which should be validated before usage. However, the current implementation proceeds without checking this return value, leading to a null pointer dereference when the code attempts to access members of the null pointer in hdmi_hdcp.c and hdmi_hpd.c modules. This pattern represents a classic software defect that falls under CWE-476, specifically null pointer dereference, and demonstrates poor defensive programming practices in kernel space code development. The vulnerability is particularly concerning as it operates within the graphics driver subsystem where such failures can cascade into broader system stability issues.
The operational impact of this vulnerability extends beyond simple system crashes to potentially enable denial of service conditions that could affect display functionality and system usability. When the null pointer dereference occurs, it typically results in a kernel oops or system crash, requiring system reboot to restore normal operation. This makes the vulnerability particularly dangerous in embedded systems or devices where automated recovery mechanisms may not be available. The attack surface is primarily limited to systems utilizing the msm hdmi driver with hdmi connectivity, but given the widespread use of linux kernel graphics drivers, the potential impact is significant. According to ATT&CK framework, this vulnerability could be leveraged as part of a broader attack chain under technique T1499.1, specifically targeting system integrity through kernel-level modifications. The vulnerability also aligns with T1547.006, as it could potentially be exploited to maintain persistence through system-level modifications that affect graphics driver behavior.
The recommended mitigation strategies involve implementing proper error handling for the alloc_ordered_workqueue return value and ensuring that all kernel subsystems validate resource allocation outcomes before proceeding with operations. System administrators should ensure their kernels are updated with the patched version that includes the proper null pointer validation. The fix implemented addresses the core issue by adding explicit checks for the return value of alloc_ordered_workqueue calls, preventing the execution path that leads to null pointer dereference. Organizations should also implement monitoring for kernel oops messages or system crashes that may indicate exploitation attempts. Additionally, maintaining updated kernel versions and applying security patches promptly is essential for protecting against similar vulnerabilities in the graphics driver subsystem. The patch itself represents a defensive programming approach that aligns with kernel development best practices and security hardening requirements.