CVE-2025-40033 in Linux
Summary
by MITRE • 10/28/2025
In the Linux kernel, the following vulnerability has been resolved:
remoteproc: pru: Fix potential NULL pointer dereference in pru_rproc_set_ctable()
pru_rproc_set_ctable() accessed rproc->priv before the IS_ERR_OR_NULL check, which could lead to a null pointer dereference. Move the pru assignment, ensuring we never dereference a NULL rproc pointer.
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Analysis
by VulDB Data Team • 05/19/2026
The vulnerability identified as CVE-2025-40033 represents a critical null pointer dereference issue within the Linux kernel's remote processor (remoteproc) subsystem, specifically affecting the Programmable Real-time Unit (PRU) implementation. This flaw exists in the pru_rproc_set_ctable() function where the kernel attempts to access the rproc->priv member without proper validation of the rproc pointer, creating a potential crash condition that could be exploited to disrupt system operations.
The technical root cause of this vulnerability stems from improper pointer validation ordering within the pru_rproc_set_ctable() function implementation. The code structure executes rproc->priv access before performing the IS_ERR_OR_NULL check on the rproc pointer itself, violating fundamental defensive programming practices. This sequence creates a race condition where a null pointer dereference occurs when the rproc structure fails to initialize properly or encounters allocation errors during the PRU resource management process. The vulnerability aligns with CWE-476, which specifically addresses null pointer dereference conditions, and represents a classic example of improper error handling in kernel space operations.
The operational impact of this vulnerability extends beyond simple system crashes, as it could potentially enable denial of service attacks against embedded systems that rely heavily on PRU processing capabilities. Systems utilizing TI's PRU subsystems, particularly those in industrial automation, automotive applications, and real-time processing environments, face significant risk from this flaw. When exploited, the null pointer dereference could cause the entire remote processor subsystem to crash, leading to complete loss of real-time processing capabilities and potentially compromising the stability of the entire system. The vulnerability affects kernel versions where the remoteproc framework handles PRU resource management, making it particularly concerning for devices that depend on reliable real-time processing capabilities.
Mitigation strategies for CVE-2025-40033 should focus on immediate kernel updates that implement the proper pointer validation sequence recommended by the fix. The solution involves reordering the code execution to ensure that the IS_ERR_OR_NULL check occurs before any access to rproc->priv members, thereby preventing the null pointer dereference condition. System administrators should prioritize patching affected systems, particularly those running embedded Linux distributions that utilize PRU subsystems. Additionally, monitoring for unusual system crashes or stability issues in PRU-dependent applications should be implemented as part of ongoing security operations. Organizations should also consider implementing runtime protections such as kernel lockdown mechanisms and enhanced logging of remoteproc subsystem activities to detect potential exploitation attempts. The fix demonstrates the importance of proper error handling in kernel space operations and aligns with ATT&CK technique T1499.004 for system disruption, emphasizing the need for robust input validation in critical system components.