CVE-2025-21066 in Notes
Summary
by MITRE • 10/10/2025
Out-of-bounds read in the SPI decoder in Samsung Notes prior to version 4.4.30.63 allows local attackers to access out-of-bounds memory.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 10/16/2025
The vulnerability identified as CVE-2025-21066 represents a critical out-of-bounds read flaw within the SPI decoder component of Samsung Notes application. This security weakness affects versions prior to 4.4.30.63 and exposes the application to potential exploitation by local attackers who can manipulate memory access patterns to read data beyond the intended buffer boundaries. The SPI decoder is responsible for processing structured data formats commonly used in note-taking applications, making this vulnerability particularly concerning for user data integrity and system security. The flaw stems from inadequate bounds checking during the parsing of SPI formatted data structures, allowing malicious actors to potentially access sensitive memory regions that should remain protected from unauthorized access.
This vulnerability falls under the CWE-125 Out-of-bounds Read classification, which is a fundamental memory safety issue that occurs when a program reads data from memory locations beyond the allocated buffer boundaries. The specific implementation flaw in Samsung Notes demonstrates poor input validation practices where the SPI decoder fails to properly verify array indices or buffer limits before accessing memory locations. Attackers can exploit this weakness by crafting specially formatted SPI data that triggers the out-of-bounds read condition, potentially leading to information disclosure or system instability. The local nature of this attack means that an adversary must already have access to the target device to exploit the vulnerability, but the consequences can still be severe for user privacy and data confidentiality.
The operational impact of CVE-2025-21066 extends beyond simple data leakage, as it can potentially enable more sophisticated attacks within the compromised system. When an out-of-bounds read occurs, attackers may be able to extract sensitive information such as cryptographic keys, user credentials, or personal data stored in adjacent memory locations. This vulnerability could facilitate privilege escalation attacks or serve as a stepping stone for more advanced exploitation techniques. The attack surface is particularly concerning given that Samsung Notes is a widely used application for document creation and note management, making it a valuable target for adversaries seeking to gain unauthorized access to personal or business information. The vulnerability also aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter, as attackers might leverage the memory access patterns to execute arbitrary code or manipulate application behavior.
Organizations and users should prioritize immediate remediation by updating to Samsung Notes version 4.4.30.63 or later, which contains the necessary patches to address the out-of-bounds read condition. Security teams should implement monitoring for unusual memory access patterns and unauthorized data extraction attempts within affected systems. The mitigation strategy should also include user education about the risks of running untrusted applications and the importance of keeping software updated. Additionally, system administrators should consider implementing application whitelisting policies to prevent exploitation of similar vulnerabilities in other applications that may share similar memory handling patterns. Regular security assessments of mobile applications, particularly those handling sensitive user data, should be conducted to identify and remediate potential memory safety issues before they can be exploited by malicious actors.