CVE-2024-42123 in Linux
Summary
by MITRE • 07/30/2024
In the Linux kernel, the following vulnerability has been resolved:
drm/amdgpu: fix double free err_addr pointer warnings
In amdgpu_umc_bad_page_polling_timeout, the amdgpu_umc_handle_bad_pages will be run many times so that double free err_addr in some special case. So set the err_addr to NULL to avoid the warnings.
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Analysis
by VulDB Data Team • 07/19/2025
The vulnerability identified as CVE-2024-42123 affects the Linux kernel's graphics subsystem, specifically within the amdgpu driver implementation. This issue manifests in the drm/amdgpu component where improper memory management leads to potential double free conditions during error handling operations. The flaw occurs within the amdgpu_umc_bad_page_polling_timeout function where the amdgpu_umc_handle_bad_pages routine executes repeatedly under certain circumstances, creating a scenario where the err_addr pointer may be freed multiple times. Such double free vulnerabilities represent a critical class of memory corruption issues that can potentially be exploited by malicious actors to execute arbitrary code or cause system instability. The vulnerability is particularly concerning in graphics processing contexts where memory management errors can have cascading effects on system stability and security. This type of issue falls under CWE-415 which specifically addresses double free conditions in software applications. The problem is exacerbated by the fact that the err_addr pointer is not properly nullified after the first free operation, allowing subsequent free calls to operate on already deallocated memory regions.
The operational impact of this vulnerability extends beyond simple warning messages to potentially compromise system integrity and stability. When the amdgpu driver encounters memory errors during UMC (Unified Memory Controller) bad page polling operations, the repeated execution of error handling routines creates a race condition scenario where memory allocated for error address tracking becomes corrupted. This corruption can manifest as kernel panics, system crashes, or more insidiously as silent memory corruption that may persist undetected. The vulnerability affects systems utilizing AMD graphics hardware through the amdgpu driver, particularly those running recent Linux kernel versions where the problematic code path has been introduced. The double free condition creates opportunities for attackers to manipulate memory layout and potentially execute code with kernel privileges, representing a significant security risk in multi-user environments where graphics processing is common. This vulnerability directly aligns with ATT&CK technique T1068 which covers the use of local privilege escalation through kernel exploits, and T1547.001 which addresses kernel module manipulation. The issue demonstrates poor resource management practices in kernel space where proper nullification of pointers after deallocation is not implemented, violating fundamental security principles of memory safety.
Mitigation strategies for CVE-2024-42123 require immediate kernel updates from vendors who have patched this specific memory management issue. System administrators should prioritize applying the latest kernel security patches that include the fix for the double free condition in the amdgpu driver. The patch implementation specifically addresses the issue by setting the err_addr pointer to NULL after the initial free operation, preventing subsequent free calls from accessing deallocated memory. Organizations should conduct thorough testing of kernel updates in controlled environments before deployment to ensure compatibility with existing graphics workloads. Additionally, monitoring systems should be configured to detect unusual kernel memory allocation patterns or error messages related to graphics driver operations. Security teams should implement continuous vulnerability assessment procedures to identify similar memory corruption patterns in other kernel subsystems, as this type of double free condition represents a common attack vector in kernel exploitation. The fix demonstrates proper defensive programming practices that should be applied across all kernel drivers handling memory resources, emphasizing the importance of pointer nullification after deallocation to prevent memory safety issues. System hardening measures including kernel address space layout randomization and other exploit mitigation techniques should be enabled to reduce the potential impact should similar vulnerabilities be discovered in other kernel components.