CVE-2023-21183 in Android
Summary
by MITRE • 06/28/2023
In ForegroundUtils of ForegroundUtils.java, there is a possible way to read NFC tag data while the app is still in the background due to a logic error in the code. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-13Android ID: A-235863754
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Analysis
by VulDB Data Team • 09/13/2025
The vulnerability identified as CVE-2023-21183 resides within the ForegroundUtils component of Android's system framework, specifically in the ForegroundUtils.java file. This flaw represents a critical security oversight that allows unauthorized access to NFC tag data even when applications are operating in the background state. The vulnerability stems from a logic error in how the system determines application foreground status, creating a window where NFC data can be accessed without proper authorization mechanisms being enforced.
The technical implementation of this vulnerability involves a flawed state management approach within the Android framework's foreground detection logic. When an application transitions between foreground and background states, the system should enforce strict access controls to sensitive data including NFC tag information. However, the logic error in ForegroundUtils fails to properly validate the application's actual foreground status, allowing background processes to potentially access NFC data through the NFC framework's read operations. This misconfiguration creates an unintended code path where NFC tag data can be read without the proper foreground context validation that should normally prevent such access.
From an operational perspective, this vulnerability enables local privilege escalation without requiring any additional execution privileges or user interaction for exploitation. The attack vector is particularly concerning because it operates silently in the background without alerting users or requiring any input from the end user. Security researchers have classified this as a local escalation of privilege vulnerability because an attacker can leverage this flaw to access NFC data that should normally be restricted to foreground applications only. The vulnerability affects Android 13 systems and is tracked under Android ID A-235863754, indicating its severity and the need for immediate attention from system administrators and security teams.
The implications of this vulnerability extend beyond simple data access, as NFC tag data often contains sensitive information including payment credentials, access control tokens, and personal identification data. The flaw creates a persistent security risk where background applications can continuously monitor and read NFC tags without proper authorization. This behavior violates fundamental security principles established in the Common Weakness Enumeration catalog, specifically relating to improper access control mechanisms and logic errors in security checks. The vulnerability aligns with ATT&CK technique T1068 which describes local privilege escalation through logic flaws in system components, making it particularly dangerous in enterprise and mobile environments where NFC functionality is commonly used.
Mitigation strategies for CVE-2023-21183 should focus on immediate system updates from Google and device manufacturers to patch the underlying ForegroundUtils logic error. Organizations should also implement monitoring solutions to detect unauthorized NFC access patterns and consider temporary restrictions on background NFC operations until patches are deployed. The fix requires proper validation of application foreground status before allowing NFC data access, ensuring that the system enforces strict context awareness for sensitive operations. Security teams must also review existing NFC-based applications and their background operation permissions to prevent exploitation of this vulnerability in custom or third-party applications that may be affected by similar logic errors in their implementation.