CVE-2025-38705 in Linux
Summary
by MITRE • 09/04/2025
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/pm: fix null pointer access
Writing a string without delimiters (' ', '\n', '\0') to the under gpu_od/fan_ctrl sysfs or pp_power_profile_mode for the CUSTOM profile will result in a null pointer dereference.
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Analysis
by VulDB Data Team • 02/10/2026
The vulnerability identified as CVE-2025-38705 resides within the Linux kernel's AMD graphics processing unit power management subsystem, specifically affecting the drm/amd/pm driver component. This issue manifests as a null pointer dereference condition that occurs when userspace applications attempt to write string data to specific sysfs interfaces associated with GPU power management controls. The affected interfaces include gpu_od/fan_ctrl and pp_power_profile_mode parameters that are part of the CUSTOM power profile configuration mechanism. The root cause stems from inadequate input validation within the kernel's power management driver code, which fails to properly handle string inputs that lack standard delimiters such as spaces, newlines, or null terminators.
This vulnerability represents a classic null pointer dereference flaw that can be categorized under CWE-476, which specifically addresses null pointer dereference conditions in software systems. The technical implementation of the flaw occurs within the kernel's sysfs interface handling code where string parsing operations do not adequately check for null pointer conditions before attempting to process user-provided input data. When a string is written to the affected sysfs nodes without proper delimiters, the kernel's parsing routine fails to initialize necessary data structures properly, leading to a scenario where a null pointer is accessed during subsequent processing operations. This condition is particularly dangerous because it can occur within kernel space, potentially allowing for privilege escalation or system instability.
The operational impact of this vulnerability extends beyond simple system crashes, as it can be exploited to cause denial of service conditions that affect graphics rendering capabilities and overall system stability. When the null pointer dereference occurs, it typically results in a kernel oops or system crash, which can disrupt graphics-intensive applications, gaming sessions, or professional visualization workloads that rely heavily on AMD GPU power management features. The vulnerability is particularly concerning in server environments where graphics processing is critical for virtualization, containerized applications, or remote desktop services that utilize AMD GPU acceleration. Additionally, this flaw can be leveraged by malicious actors to potentially escalate privileges or cause persistent system instability, especially when combined with other kernel vulnerabilities or in environments where automatic system recovery mechanisms are not properly configured.
Mitigation strategies for CVE-2025-38705 should focus on both immediate patch application and defensive configuration measures. The primary resolution involves applying the kernel patch that implements proper input validation and null pointer checks within the drm/amd/pm driver code. System administrators should prioritize updating to kernel versions that contain the fix, particularly in production environments where AMD GPU power management features are actively utilized. Organizations should also implement monitoring solutions that can detect anomalous sysfs access patterns to the affected gpu_od/fan_ctrl and pp_power_profile_mode interfaces, as these access patterns may indicate attempted exploitation. From a defensive standpoint, implementing proper input sanitization at the application level before writing to sysfs interfaces can provide additional protection layers, though the primary fix must be applied at the kernel level. The vulnerability also highlights the importance of proper kernel security testing and validation of sysfs interface implementations, particularly for power management and device control subsystems that are frequently accessed by user-space applications.