CVE-2024-46823 in Linux
Summary
by MITRE • 09/27/2024
In the Linux kernel, the following vulnerability has been resolved:
kunit/overflow: Fix UB in overflow_allocation_test
The 'device_name' array doesn't exist out of the 'overflow_allocation_test' function scope. However, it is being used as a driver name when calling 'kunit_driver_create' from 'kunit_device_register'. It produces the kernel panic with KASAN enabled.
Since this variable is used in one place only, remove it and pass the device name into kunit_device_register directly as an ascii string.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 04/04/2026
The vulnerability identified as CVE-2024-46823 resides within the Linux kernel's KUnit testing framework, specifically affecting the overflow_allocation_test functionality. This issue demonstrates a classic case of undefined behavior stemming from improper variable scoping and memory management practices. The vulnerability occurs in the kernel's testing infrastructure rather than in core operational code, yet it represents a significant concern for kernel developers and security researchers who rely on KUnit for comprehensive testing of kernel components. The flaw manifests when KASAN (Kernel Address Sanitizer) is enabled, indicating that the issue involves memory safety violations that could potentially be exploited to compromise kernel stability and security.
The technical root cause of this vulnerability lies in the improper handling of the device_name array variable within the overflow_allocation_test function scope. The array is declared within a specific function context but is subsequently referenced outside of that scope when calling kunit_driver_create from within kunit_device_register. This creates a scenario where the kernel attempts to access memory that has either been deallocated or is otherwise inaccessible, leading to kernel panic conditions. The vulnerability represents a violation of memory safety principles and falls under the category of use-after-free or out-of-scope memory access patterns that are commonly classified as undefined behavior in software development practices. According to CWE guidelines, this corresponds to CWE-416: Use After Free, as the memory location referenced by device_name is no longer valid when accessed in the subsequent function call.
The operational impact of this vulnerability extends beyond simple testing failures, as it demonstrates a fundamental flaw in kernel testing infrastructure that could potentially be indicative of broader memory management issues within the kernel codebase. When KASAN is enabled, which is commonly used in security-sensitive environments and kernel development, this undefined behavior causes immediate kernel panics, effectively halting system operation and making the affected testing environment unusable. The fact that this occurs within KUnit testing infrastructure suggests that developers might inadvertently introduce similar patterns in production code, creating potential security risks that could be exploited in more sophisticated attack scenarios. The vulnerability's manifestation through kernel panic indicates that it operates at a fundamental level of kernel memory management, potentially compromising the integrity of the kernel's memory subsystem.
The mitigation strategy for CVE-2024-46823 involves a straightforward code refactoring approach that eliminates the problematic variable scope issue by passing the device name directly as an ASCII string parameter to kunit_device_register. This solution addresses the root cause by ensuring that all data required for the function call is properly scoped and accessible within the appropriate context. The fix aligns with best practices for kernel development and memory management, as it removes the undefined behavior by eliminating the out-of-scope variable reference. This remediation approach is consistent with ATT&CK framework considerations for kernel-level vulnerabilities, where the focus remains on preventing memory safety issues that could lead to system instability or potential privilege escalation. The solution also demonstrates proper defensive programming practices that should be applied throughout kernel development to prevent similar issues in other testing and production code components. The fix ensures that all memory access patterns are valid and that the kernel's memory management subsystem remains intact during testing operations, thereby maintaining system stability and security.