CVE-2022-20454 in Android
Summary
by MITRE • 11/09/2022
In fdt_next_tag of fdt.c, there is a possible out of bounds write due to an integer overflow. This could lead to local escalation of privilege with System execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-10 Android-11 Android-12 Android-12L Android-13Android ID: A-242096164
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Analysis
by VulDB Data Team • 04/15/2026
The vulnerability identified as CVE-2022-20454 represents a critical integer overflow condition within the flattened device tree (FDT) parsing functionality of Android systems. This flaw exists specifically within the fdt_next_tag function located in the fdt.c source file, which is responsible for processing device tree blobs that describe hardware configurations to the operating system. The integer overflow occurs during the calculation of memory boundaries when traversing device tree tags, creating a scenario where the system may attempt to write data beyond the allocated memory buffer. This type of vulnerability falls under the CWE-190 category of integer overflow, which is a well-documented weakness that has been exploited in numerous security incidents across various platforms and operating systems.
The technical implementation of this vulnerability allows for a local privilege escalation attack that requires system execution privileges to be initially compromised. While no user interaction is necessary for exploitation, the attacker must first gain access to a system with execution capabilities, typically through a previous compromise or by leveraging another vulnerability. The nature of the integer overflow means that when the system processes malformed device tree data, the calculation of the next tag position can result in an unexpectedly large value that exceeds the bounds of the allocated memory region. This overflow condition creates a writable memory location that can be manipulated to overwrite adjacent memory segments, potentially including critical system structures or function pointers.
The operational impact of this vulnerability extends beyond simple memory corruption, as it provides a pathway for local privilege escalation that could allow an attacker to gain elevated system privileges. This is particularly concerning in Android environments where the device tree parsing occurs during the boot process and system initialization phases, making it a potential attack vector for persistent malware or rootkits. The vulnerability affects multiple Android versions including Android 10 through Android 13, indicating that it has been present in the codebase for several years and affects a substantial portion of the Android ecosystem. The Android ID A-242096164 assigned to this vulnerability reflects its severity and the coordinated disclosure process that typically accompanies such findings in the Android security ecosystem.
Mitigation strategies for CVE-2022-20454 should focus on implementing proper bounds checking and integer overflow protection mechanisms within the device tree parsing code. The recommended approach involves validating all integer calculations used in memory boundary computations and ensuring that arithmetic operations do not exceed the maximum representable values for the target platform. Security patches should include explicit bounds checking before any memory writes occur, particularly in functions that traverse device tree structures. Organizations should prioritize patching affected Android systems immediately, as the vulnerability's low exploitation requirements and potential for privilege escalation make it an attractive target for malicious actors. The ATT&CK framework categorizes this vulnerability under privilege escalation techniques, specifically targeting the execution of malicious code with elevated privileges through memory corruption attacks. System administrators should also implement monitoring for unusual device tree parsing activities and consider runtime protections such as address space layout randomization and stack canaries to further reduce the exploitability of this and similar vulnerabilities.