CVE-2026-64279 in Linux
Summary
by MITRE • 07/25/2026
In the Linux kernel, the following vulnerability has been resolved:
i2c: core: fix adapter deregistration race
Adapters can be looked up by their id using i2c_get_adapter() which takes a reference to the embedded struct device.
Remove the adapter from the IDR before tearing it down during deregistration (and on registration failure) to make sure its resources are not accessed after having been freed (e.g. the device name).
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Analysis
by VulDB Data Team • 07/25/2026
This vulnerability represents a critical race condition in the Linux kernel's I2C subsystem that could lead to system instability and potential security implications. The issue occurs during the deregistration process of I2C adapters where concurrent access patterns create opportunities for memory corruption and undefined behavior. When an I2C adapter is being removed from the system, the kernel must ensure proper synchronization between lookup operations and resource cleanup processes.
The technical flaw stems from the improper ordering of operations during adapter deregistration within the i2c core subsystem. Specifically, when i2c_get_adapter() is called to look up adapters by their identifier, it takes a reference to the embedded struct device which maintains the adapter's lifecycle state. The race condition manifests because the adapter is not removed from the Internal Dynamic Reclaimer (IDR) data structure before its resources are torn down during the deregistration process. This sequence allows concurrent threads or processes to access a freed adapter resource, potentially leading to use-after-free conditions and memory corruption.
The operational impact of this vulnerability extends beyond simple system crashes to include potential privilege escalation opportunities and denial of service scenarios. Attackers could exploit this race condition to manipulate I2C device operations, potentially gaining unauthorized access to hardware interfaces or causing system-wide instability. The vulnerability particularly affects systems with active I2C communication where multiple threads might simultaneously attempt to access adapter resources during the deregistration phase.
From a cybersecurity perspective, this issue aligns with CWE-362 (Concurrent Execution using Shared Resource with Unprotected Critical Section) and represents a classic race condition that can be leveraged in various attack vectors. The ATT&CK framework would categorize this as a system modification technique where an adversary could manipulate kernel data structures to achieve persistent access or system compromise. The vulnerability demonstrates the critical importance of proper resource management and synchronization primitives in kernel space operations.
The mitigation strategy involves ensuring proper ordering of operations during adapter deregistration by removing the adapter from the IDR before initiating resource cleanup procedures. This change prevents lookup operations from accessing freed memory locations while maintaining the integrity of the I2C subsystem's device management functionality. The fix requires careful consideration of all code paths that could lead to registration failure scenarios, ensuring consistent behavior across both successful and failed registration attempts.
Security researchers should monitor for potential exploitation patterns in embedded systems or server environments where I2C devices are actively managed during system operations. Organizations running Linux-based systems with active I2C infrastructure should prioritize patching this vulnerability as it represents a foundational security issue that could be leveraged to compromise system integrity and potentially escalate privileges within the kernel space. The fix demonstrates the importance of maintaining proper synchronization mechanisms in concurrent kernel subsystems where multiple threads may access shared resources simultaneously.
This vulnerability underscores the critical nature of kernel-level race condition prevention and highlights the need for comprehensive testing of concurrent access patterns in device drivers. The solution emphasizes the principle of resource ordering and proper cleanup sequence that prevents dangling references to freed memory structures. System administrators should verify that all systems with I2C capabilities have been updated to include this fix, particularly in production environments where stability and security are paramount considerations.