CVE-2026-64249 in Linux
Summary
by MITRE • 07/24/2026
In the Linux kernel, the following vulnerability has been resolved:
fpga: region: fix use-after-free in child_regions_with_firmware()
Move of_node_put(child_region) after the error print to avoid accessing freed memory when pr_err() references child_region.
[ Yilun: Fix the Fixes tag ]
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Analysis
by VulDB Data Team • 07/24/2026
This vulnerability represents a classic use-after-free condition that occurs within the Linux kernel's FPGA region subsystem, specifically in the child_regions_with_firmware() function. The flaw demonstrates a critical memory management error where the device tree node reference is released before all potential references to it have been completed. When an error occurs during firmware processing for FPGA regions, the code attempts to print an error message using pr_err() which references the child_region variable that has already been freed through move of_node_put() call. This creates a situation where subsequent memory access patterns attempt to dereference a pointer to freed memory, leading to potential system instability and security implications.
The technical implementation reveals a race condition in resource cleanup ordering where the kernel's device tree node reference counting mechanism fails to maintain proper lifecycle management for FPGA region child nodes. The vulnerability stems from improper sequence of operations where the reference count is decremented and the memory is released before error reporting completes, violating fundamental principles of safe memory management in kernel space operations. This type of flaw commonly maps to CWE-416: Use After Free, which is classified as a critical vulnerability category in the Common Weakness Enumeration framework.
The operational impact of this vulnerability extends beyond simple system crashes, potentially enabling privilege escalation attacks or denial of service conditions within embedded systems that rely heavily on FPGA configuration and management. In environments where FPGA regions are dynamically managed and firmware updates occur frequently, this flaw could be exploited to cause system instability or create persistent denial of service conditions. The vulnerability affects any Linux kernel version that implements the FPGA region subsystem and is particularly concerning in industrial control systems, network infrastructure devices, and embedded platforms where FPGA configurations are critical for system operation.
Mitigation strategies should focus on implementing proper resource management ordering within kernel subsystems to ensure that all references to freed memory are completed before memory release operations occur. The fix involves reordering the code execution sequence to move the of_node_put() call after error reporting has completed, ensuring that pr_err() can safely access the child_region reference without accessing freed memory. This aligns with ATT&CK technique T1068: Exploitation for Privilege Escalation and represents a fundamental requirement for kernel security hardening. System administrators should prioritize applying patches that correct this resource management ordering issue, particularly in production environments where FPGA-based systems operate under high availability requirements. The vulnerability highlights the importance of thorough code review processes for kernel subsystems and proper adherence to memory management best practices in critical system components.