CVE-2022-20583 in Android
Summary
by MITRE • 12/16/2022
In ppmp_unprotect_mfcfw_buf of drm_fw.c, there is a possible out of bounds write due to improper input validation. This could lead to local escalation of privilege in S-EL1 with System execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android kernelAndroid ID: A-234859169References: N/A
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Analysis
by VulDB Data Team • 04/22/2026
The vulnerability identified as CVE-2022-20583 resides within the Android kernel's drm_fw.c file, specifically in the ppmp_unprotect_mfcfw_buf function. This flaw represents a critical security weakness that could enable local privilege escalation from user mode to supervisor mode level one. The vulnerability manifests as an out-of-bounds write condition that occurs when the system fails to properly validate input parameters during firmware buffer handling operations. Such a condition typically arises when the kernel attempts to write data beyond the allocated memory boundaries of a buffer, potentially corrupting adjacent memory regions.
The technical implementation of this vulnerability involves improper input validation mechanisms within the ppmp_unprotect_mfcfw_buf function, which processes memory protection operations for firmware buffers. When the function receives unvalidated input parameters, it fails to perform adequate bounds checking before executing memory write operations. This allows an attacker with local system access to manipulate the input data in such a way that causes the function to write beyond the intended buffer limits. The vulnerability requires system execution privileges to exploit, indicating that the attacker must already have some level of system access but not necessarily elevated privileges. The lack of user interaction requirement makes this vulnerability particularly concerning as it can be exploited automatically without requiring user engagement.
The operational impact of this vulnerability extends beyond simple memory corruption, as it enables local privilege escalation to S-EL1, which represents a significant security compromise. In the ARM architecture context, S-EL1 corresponds to supervisor mode execution level where the kernel operates with elevated privileges and system-level access. This privilege escalation capability allows an attacker to gain control over critical system functions, potentially enabling further exploitation including arbitrary code execution, system compromise, and complete control over the device. The vulnerability affects Android kernel implementations and has been assigned Android ID A-234859169, indicating its specific relevance to Android security infrastructure.
From a cybersecurity perspective, this vulnerability aligns with CWE-787, which describes out-of-bounds write conditions, and represents a classic example of improper input validation leading to memory corruption. The ATT&CK framework would categorize this vulnerability under privilege escalation techniques, specifically using kernel-level exploits to gain elevated privileges. The exploitation pathway typically involves local system access, potentially through compromised applications or existing user accounts, followed by precise manipulation of the firmware buffer handling functions. Security organizations should prioritize patching this vulnerability as it provides a direct path for attackers to escalate privileges without requiring user interaction, making it particularly dangerous in environments where local access is possible.
Mitigation strategies for CVE-2022-20583 should focus on immediate patch deployment from Android security updates, implementing additional input validation checks within the affected function, and monitoring for potential exploitation attempts. System administrators should also consider implementing runtime protections such as stack canaries, address space layout randomization, and kernel address space layout randomization to make exploitation more difficult. Regular security audits of kernel components and input validation mechanisms should be conducted to identify similar vulnerabilities. Additionally, organizations should maintain comprehensive monitoring for unauthorized local access attempts and anomalous system behavior that might indicate exploitation attempts. The vulnerability demonstrates the critical importance of robust input validation in kernel-level code and highlights the need for continuous security assessment of core system components that handle memory operations and privilege transitions.