CVE-2026-28644 in Android
Summary
by MITRE • 09/08/2026
In startNextMatchingActivity of ActivityTaskManagerService.java, there is a possible permission bypass due to a confused deputy. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.
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Analysis
by VulDB Data Team • 09/08/2026
The vulnerability identified in the Android operating system's ActivityTaskManagerService presents a critical security flaw rooted in improper access control mechanisms, specifically manifesting as a confused deputy problem within the startNextMatchingActivity method of ActivityTaskManagerService.java. This architectural weakness allows an application or process to act on behalf of another entity without proper authorization checks, effectively bypassing intended permission boundaries. The core issue lies in how the system handles intent resolution and activity launching, where the service fails to adequately verify that the requesting component has the legitimate authority to initiate a specific target activity under all contextual conditions. This misconfiguration creates an avenue for local privilege escalation, enabling malicious actors to gain higher levels of access than originally granted by the operating system's security model.
From a technical perspective, this vulnerability exploits the trust relationship between different components within the Android framework. When startNextMatchingActivity is invoked, it processes intents that may contain data or flags intended for privileged system services or sensitive applications. Due to the confused deputy flaw, an unprivileged application can manipulate these parameters to trick the system into performing actions reserved for higher-privilege contexts. This bypass does not require complex exploitation techniques such as buffer overflows or memory corruption; instead, it relies on logical errors in permission validation logic. Consequently, no additional execution privileges are needed beyond what is typically granted to a standard third-party application, making this vulnerability particularly dangerous and easy to exploit for attackers with local access.
The operational impact of this flaw is significant, as it facilitates the unauthorized escalation of privileges from an untrusted user space context to more sensitive system-level operations. An attacker leveraging this vulnerability could potentially intercept or modify data belonging to other applications, bypass security restrictions imposed by the Android permission model, and execute commands that should be restricted to system processes. This compromises the integrity and confidentiality of the device's ecosystem, allowing for potential surveillance, data theft, or further lateral movement within the operating environment. Since user interaction is not required for exploitation, the attack surface is broadened considerably, as background services or automated scripts can trigger this flaw without any visible activity from the end-user, increasing the likelihood of successful compromise in real-world scenarios.
To mitigate this risk, developers and system integrators must ensure that ActivityTaskManagerService.java undergoes rigorous code review focusing on access control lists and permission verification logic during intent processing. Implementing strict checks to validate the caller's identity and permissions before proceeding with activity matching is essential. Furthermore, adhering to the principle of least privilege ensures that components only have access to resources necessary for their function. Security patches released by Android maintainers should be applied promptly to address this specific logical flaw in the framework layer. Organizations relying on affected devices must also enforce strict application sandboxing policies and monitor for anomalous behavior indicative of privilege escalation attempts, aligning with industry standards such as CWE-269 which addresses improper authorization checks that allow a confused deputy scenario.
This vulnerability is closely related to ATT&CK technique T1055, Process Injection, or more accurately in this context, T1078 Valid Accounts and subsequent lateral movement techniques, although it primarily represents an initial access vector through privilege escalation rather than traditional injection methods. It also aligns with CWE-269: Improper Privilege Management, where the system fails to correctly enforce permissions during critical operations. By addressing these logical inconsistencies in the ActivityTaskManagerService, the Android platform can restore its intended security posture and prevent unauthorized elevation of privileges that undermine user trust and device safety.