CVE-2023-53851 in Linux
Summary
by MITRE • 12/09/2025
In the Linux kernel, the following vulnerability has been resolved:
drm/msm/dp: Drop aux devices together with DP controller
Using devres to depopulate the aux bus made sure that upon a probe deferral the EDP panel device would be destroyed and recreated upon next attempt.
But the struct device which the devres is tied to is the DPUs (drm_dev->dev), which may be happen after the DP controller is torn down.
Indications of this can be seen in the commonly seen EDID-hexdump full of zeros in the log, or the occasional/rare KASAN fault where the panel's attempt to read the EDID information causes a use after free on DP resources.
It's tempting to move the devres to the DP controller's struct device, but the resources used by the device(s) on the aux bus are explicitly torn down in the error path. The KASAN-reported use-after-free also remains, as the DP aux "module" explicitly frees its devres-allocated memory in this code path.
As such, explicitly depopulate the aux bus in the error path, and in the component unbind path, to avoid these issues.
Patchwork: https://patchwork.freedesktop.org/patch/542163/
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Analysis
by VulDB Data Team • 03/30/2026
The vulnerability described in CVE-2023-53851 affects the Linux kernel's display subsystem, specifically within the drm/msm/dp driver component. This issue manifests in the improper handling of auxiliary bus devices during display port controller operations, creating a scenario where device resources are not correctly managed during error conditions or system unbinding events. The problem stems from the use of devres (device resource management) mechanisms that tie auxiliary device lifecycles to the display processing unit's device structure rather than the display port controller itself, leading to timing issues in resource cleanup.
The technical flaw occurs when the devres management system attempts to destroy and recreate EDP panel devices upon probe deferral events. The struct device that devres is associated with points to the DPUs (drm_dev->dev) which may be destroyed after the DP controller has already been torn down. This misalignment in resource management creates a window where auxiliary bus devices can be improperly handled, resulting in critical system instability. The vulnerability is particularly evident in the form of EDID hexdump logs filled with zeros, indicating failed EDID reading operations, and KASAN (Kernel Address Sanitizer) faults where panel attempts to read EDID information cause use-after-free errors on display port resources.
The operational impact of this vulnerability extends beyond simple display functionality degradation to potentially compromising system stability and security. When the display subsystem encounters error conditions or undergoes component unbind operations, the improper resource management can lead to kernel crashes, memory corruption, and potentially exploitable conditions. The use-after-free scenarios described in the KASAN reports represent particularly concerning security implications as they could be leveraged to execute arbitrary code within kernel space, making this vulnerability relevant to both system reliability and security posture. This issue directly relates to CWE-415 which addresses double free conditions and CWE-416 which covers use after free vulnerabilities in memory management systems.
The mitigation strategy involves explicitly depopulating the auxiliary bus in both error paths and component unbind scenarios, rather than relying solely on the devres management system's automatic cleanup. This approach ensures that auxiliary devices are properly handled regardless of the timing of resource destruction relative to the display controller's lifecycle. The patch implementation addresses the root cause by implementing explicit cleanup procedures that prevent the race conditions between device destruction and resource access, thereby eliminating the use-after-free scenarios that could lead to system instability or security exploits. This solution aligns with ATT&CK framework techniques related to system resource manipulation and kernel exploitation prevention, ensuring that the display subsystem maintains proper resource management boundaries during all operational states.