CVE-2025-21784 in Linux
Summary
by MITRE • 02/27/2025
In the Linux kernel, the following vulnerability has been resolved:
drm/amdgpu: bail out when failed to load fw in psp_init_cap_microcode()
In function psp_init_cap_microcode(), it should bail out when failed to load firmware, otherwise it may cause invalid memory access.
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Analysis
by VulDB Data Team • 05/25/2026
The vulnerability identified as CVE-2025-21784 resides within the Linux kernel's graphics driver subsystem, specifically affecting the amdgpu driver implementation. This flaw manifests in the drm/amdgpu component where the psp_init_cap_microcode() function fails to properly handle firmware loading failures, creating a critical pathway for potential system instability and memory corruption. The issue occurs during the initialization phase of the AMD GPU's PSP (Platform Security Processor) capabilities, where firmware components are essential for proper hardware operation and security features.
The technical flaw represents a classic error handling failure that can be categorized under CWE-459, which deals with incomplete cleanup and improper handling of resources. When firmware loading operations fail within the psp_init_cap_microcode() function, the code continues execution instead of terminating gracefully, leading to a scenario where invalid memory access patterns can occur. This improper error handling creates a condition where the driver attempts to reference memory locations that have not been properly initialized or validated, potentially allowing for arbitrary code execution or system crashes. The vulnerability directly impacts the kernel's memory management and can be exploited to disrupt normal system operation or potentially escalate privileges.
The operational impact of this vulnerability extends beyond simple system instability, as it affects the core graphics functionality and security posture of Linux systems utilizing AMD GPUs. When firmware loading fails and the driver does not bail out as expected, the system may continue operating with incomplete or corrupted firmware state, leading to potential denial of service conditions or more severe security implications. This issue particularly affects systems where the PSP firmware is critical for GPU security features, including secure boot processes and hardware-level protection mechanisms. The vulnerability can be triggered during system boot or runtime initialization of AMD GPU devices, making it a persistent threat to system reliability and security.
Mitigation strategies for CVE-2025-21784 primarily focus on applying the relevant kernel patches that implement proper error handling in the psp_init_cap_microcode() function. System administrators should prioritize updating their Linux kernels to versions that contain the resolved vulnerability, as this addresses the root cause of the improper error handling. The fix ensures that when firmware loading operations fail, the driver properly terminates execution rather than continuing with potentially invalid state. Additionally, monitoring systems should be implemented to detect unusual firmware loading patterns or memory access violations that could indicate exploitation attempts. Organizations should also consider implementing runtime protections such as kernel address space layout randomization and stack canaries to further reduce the attack surface. This vulnerability aligns with ATT&CK technique T1059.001 for executing malicious code through kernel-level exploits and T1499.004 for system disruption through denial of service conditions.