CVE-2023-23005 in Linux
Summary
by MITRE • 03/01/2023
In the Linux kernel before 6.2, mm/memory-tiers.c misinterprets the alloc_memory_type return value (expects it to be NULL in the error case, whereas it is actually an error pointer).
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Analysis
by VulDB Data Team • 10/06/2025
The vulnerability identified as CVE-2023-23005 represents a critical flaw in the Linux kernel's memory management subsystem, specifically within the mm/memory-tiers.c component. This issue affects kernel versions prior to 6.2 and stems from a fundamental misunderstanding of how the alloc_memory_type function handles error conditions. The flaw manifests when the kernel attempts to manage memory tiers and encounters a scenario where memory allocation fails, but the error handling logic incorrectly interprets the return value from alloc_memory_type. This misinterpretation creates a potential security risk that could be exploited to compromise system stability and potentially escalate privileges.
The technical root cause of this vulnerability lies in the improper handling of error pointers within the memory tiering subsystem. When alloc_memory_type fails to allocate memory for tier management, it returns an error pointer rather than a NULL value as the code expects. This discrepancy occurs because the kernel code assumes that all error conditions result in a NULL return value, but error pointers are the standard mechanism used by the Linux kernel to signal allocation failures. The memory-tiers.c module contains a critical logic error where it fails to properly check for error pointer conditions using the IS_ERR macro or similar kernel conventions, leading to incorrect handling of failed memory allocations. This error handling flaw is particularly concerning because it exists within the core memory management pathways that are frequently accessed during system operation.
The operational impact of this vulnerability extends beyond simple system instability, as it can potentially be leveraged by malicious actors to cause denial of service conditions or gain unauthorized access to system resources. When memory allocation fails within the tiering subsystem, the improper error handling could lead to kernel panics, system crashes, or more insidiously, allow for privilege escalation attacks. The vulnerability affects systems that utilize memory tiering features, which are increasingly common in modern server and desktop environments where heterogeneous memory architectures are employed. Attackers could potentially exploit this weakness by triggering memory allocation failures in a controlled manner, causing the kernel to misinterpret these failures and execute unintended code paths that could lead to system compromise. This flaw particularly impacts enterprise environments where memory tiering is commonly deployed in high-performance computing scenarios.
Mitigation strategies for CVE-2023-23005 primarily involve upgrading to Linux kernel version 6.2 or later, where the memory management subsystem has been corrected to properly handle error pointers from alloc_memory_type. System administrators should prioritize patching affected systems, especially those running memory-intensive applications or serving critical infrastructure roles. Additional defensive measures include implementing monitoring solutions to detect anomalous memory allocation patterns that might indicate exploitation attempts, and conducting thorough security audits of systems that rely on memory tiering features. Organizations should also consider implementing kernel lockdown mechanisms and ensuring that only authorized users have access to systems where memory tiering is enabled, as this reduces the attack surface for potential exploitation. The vulnerability aligns with CWE-252, which addresses improper checking of return values, and could potentially map to ATT&CK technique T1068, involving exploitation of remote services, if exploited through network-based attack vectors.