CVE-2022-20364 in Android
Summary
by MITRE • 09/14/2022
In sysmmu_unmap of TBD, there is a possible out of bounds write due to a missing bounds check. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android kernelAndroid ID: A-233606615References: N/A
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Analysis
by VulDB Data Team • 04/12/2026
The vulnerability identified as CVE-2022-20364 resides within the sysmmu_unmap function of the Android kernel's memory management subsystem, specifically affecting the System Memory Management Unit implementation. This represents a critical security flaw that demonstrates a classic out-of-bounds write condition, where the kernel fails to validate memory access boundaries during memory unmapping operations. The vulnerability manifests in the absence of proper bounds checking mechanisms that should prevent memory operations from extending beyond allocated buffer limits, creating a potential pathway for malicious code execution and privilege escalation.
The technical implementation flaw stems from insufficient input validation within the sysmmu_unmap function, which processes memory unmap requests from user-space applications. When the kernel receives memory management commands, it fails to verify that the requested unmapping operations remain within valid memory boundaries, allowing for potential buffer overflow conditions. This missing bounds check creates an exploitable condition where an attacker can manipulate memory addresses to write data beyond the intended memory regions, potentially corrupting critical kernel data structures or executing arbitrary code with elevated privileges. The vulnerability operates at the kernel level, making it particularly dangerous as it can be exploited without requiring additional execution privileges or user interaction.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it represents a fundamental breakdown in kernel memory protection mechanisms. An attacker with local access could leverage this flaw to gain root-level privileges, effectively bypassing all standard security controls and access restrictions. The lack of user interaction requirements means that exploitation can occur automatically when legitimate memory management operations are performed, making this vulnerability particularly insidious. This condition directly violates the principle of least privilege and undermines the kernel's ability to maintain system integrity, potentially allowing attackers to modify critical system files, disable security features, or establish persistent backdoors within the Android operating system.
Mitigation strategies for CVE-2022-20364 should focus on implementing comprehensive bounds checking mechanisms within the sysmmu_unmap function and related memory management routines. System administrators should prioritize applying security patches provided by Android kernel maintainers, as these updates typically include proper bounds validation and memory access controls. The fix should incorporate defensive programming practices that validate all memory access operations against allocated buffer boundaries, preventing unauthorized memory writes. Organizations should also implement monitoring solutions to detect anomalous memory management operations that could indicate exploitation attempts, while adhering to the principle of least privilege and maintaining regular security assessments of kernel components. This vulnerability aligns with CWE-129, which addresses insufficient bounds checking in memory management operations, and represents a clear violation of the ATT&CK technique T1068, which involves the exploitation of legitimate credentials or privileges for privilege escalation.