CVE-2022-50887 in Linux
Summary
by MITRE • 12/30/2025
In the Linux kernel, the following vulnerability has been resolved:
regulator: core: fix unbalanced of node refcount in regulator_dev_lookup()
I got the the following report:
OF: ERROR: memory leak, expected refcount 1 instead of 2, of_node_get()/of_node_put() unbalanced - destroy cset entry: attach overlay node /i2c/pmic@62/regulators/exten
In of_get_regulator(), the node is returned from of_parse_phandle() with refcount incremented, after using it, of_node_put() need be called.
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Analysis
by VulDB Data Team • 04/26/2026
The vulnerability CVE-2022-50887 represents a critical reference counting imbalance in the Linux kernel's device tree regulator subsystem, specifically within the regulator_dev_lookup() function. This issue stems from improper handling of device tree node references during regulator device lookups, creating a memory management flaw that can lead to resource leaks and potential system instability. The problem manifests when the kernel attempts to process device tree overlays, particularly when dealing with regulator devices that are part of complex power management configurations. The vulnerability directly impacts the kernel's ability to properly manage reference counts for device tree nodes, which are essential for maintaining proper memory allocation and deallocation cycles.
The technical flaw occurs in the of_get_regulator() function where device tree nodes are retrieved using of_parse_phandle() which increments the reference count of the node. However, the subsequent code path fails to properly decrement this reference count through the required of_node_put() call, leading to an unbalanced reference count scenario. This creates a memory leak condition where the device tree node remains allocated in memory even after it should have been released, as evidenced by the error message indicating expected refcount 1 instead of 2. The specific context involves the destruction of cset entries during overlay attachment operations, particularly when processing overlay nodes such as /i2c/pmic@62/regulators/exten. This pattern of improper reference counting violates fundamental kernel memory management principles and can accumulate over time, potentially leading to system resource exhaustion.
The operational impact of this vulnerability extends beyond simple memory leaks to potentially compromise system stability and security. When reference counts become unbalanced, it can cause cascading failures in device tree parsing operations, leading to regulator device initialization failures or incomplete power management configurations. The vulnerability is particularly concerning in embedded systems and mobile devices where memory resources are constrained and proper resource management is critical for system reliability. Attackers could potentially exploit this memory leak to cause denial of service conditions or, in combination with other vulnerabilities, create more severe system instability. The issue affects systems using device tree overlays for dynamic hardware configuration, which are common in modern Linux systems including automotive infotainment systems, network infrastructure devices, and mobile platforms. This vulnerability aligns with CWE-401 Memory Leak and CWE-470 Use of Externally-Controlled Input to Select Classes or Code, as it represents improper resource management that can be triggered through device tree overlay operations.
Mitigation strategies for CVE-2022-50887 focus on correcting the reference counting logic in the regulator subsystem to ensure proper balance between of_node_get() and of_node_put() calls. The fix requires implementing proper reference count management in the of_get_regulator() function and related regulator lookup operations to ensure that every node reference obtained through of_parse_phandle() is properly released. System administrators should ensure their kernels are updated to versions containing the patched regulator subsystem code, which typically involves applying the specific kernel patch that corrects the reference counting imbalance. Organizations should also implement monitoring for memory usage patterns that could indicate resource leaks, particularly in systems that frequently apply device tree overlays or manage complex power configurations. The fix demonstrates the importance of proper device tree node management in kernel space and aligns with ATT&CK technique T1068 Exploitation for Privilege Escalation, as improper reference counting can create conditions that lead to privilege escalation or system compromise through resource exhaustion attacks. Regular kernel updates and proper testing of device tree overlay configurations are essential preventive measures against this class of vulnerabilities.