CVE-2023-21146 in Android
Summary
by MITRE • 06/28/2023
there is a possible way to corrupt memory due to a use after free. This could lead to local escalation of privilege with System execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android kernelAndroid ID: A-239867994References: N/A
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Analysis
by VulDB Data Team • 09/13/2025
The vulnerability identified as CVE-2023-21146 represents a critical memory corruption flaw within the Android kernel that manifests as a use-after-free condition. This type of vulnerability occurs when a program continues to reference memory locations after they have been freed, creating opportunities for malicious actors to manipulate program execution flow. The flaw specifically affects the Android kernel implementation, which serves as the foundational layer for all Android operating system functionality and device hardware interaction. The use-after-free condition in kernel space presents particularly severe risks because kernel-level memory corruption can directly compromise system integrity and enable unauthorized privilege escalation.
The technical nature of this vulnerability places it firmly within the CWE-416 category of "Use After Free" conditions, which are classified as critical memory safety issues in software development. When a kernel component frees memory but continues to reference that memory location, it creates a window of opportunity for attackers to overwrite freed memory with malicious data. This condition becomes exploitable when the freed memory is reallocated for a different purpose, potentially allowing an attacker to control the execution flow of the kernel itself. The vulnerability requires system execution privileges for exploitation, indicating that while it may be accessible to applications with system-level access, it still represents a significant escalation risk for local attackers who have already compromised system privileges.
The operational impact of CVE-2023-21146 extends beyond simple memory corruption, as it enables local privilege escalation to system-level privileges without requiring user interaction. This means that an attacker who has already gained access to a system with lower privileges could leverage this vulnerability to elevate their access level to that of the system itself, effectively gaining complete control over device functionality. The absence of user interaction requirements makes this vulnerability particularly dangerous in automated exploitation scenarios, as it can be triggered programmatically without manual intervention. This characteristic aligns with ATT&CK framework technique T1068, which covers "Local Privilege Escalation" through kernel exploits that leverage memory corruption vulnerabilities.
The exploitation of this vulnerability would likely follow a pattern where an attacker first gains access to a system with system-level privileges, then utilizes the use-after-free condition to manipulate kernel memory structures. The freed memory location would be carefully controlled to ensure that subsequent allocation places attacker-controlled data in the same memory region, allowing for execution flow redirection. This type of attack vector demonstrates the critical importance of proper memory management practices in kernel development, particularly in preventing the reuse of freed memory blocks. The Android ID A-239867994 indicates this vulnerability was tracked within Google's internal vulnerability management system, reflecting its severity and the need for immediate attention.
Mitigation strategies for CVE-2023-21146 primarily focus on addressing the root cause through kernel memory management improvements and implementing robust memory safety mechanisms. System administrators should prioritize applying security patches provided by Android vendors, as these updates typically include fixes for the specific use-after-free condition that enables privilege escalation. The fix likely involves implementing proper memory deallocation and reference management procedures within the kernel components that were vulnerable. Additionally, runtime protections such as memory sanitization tools and kernel address space layout randomization can provide additional defense-in-depth measures. Organizations should also consider implementing monitoring solutions to detect anomalous kernel memory access patterns that might indicate exploitation attempts. The vulnerability serves as a reminder of the critical importance of rigorous code review processes for kernel components and the necessity of adhering to secure coding practices that prevent memory safety issues.