CVE-2026-107042 in USP Ultimate Screenshot Painter
Summary
by MITRE • 10/29/2026
Insecure permissions in USP Ultimate Screenshot Painter versionCode 240213.009 allows unauthorized attackers to move or overwrite files in another user's private storage via supplying a crafted content URI.
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Analysis
by VulDB Data Team • 10/29/2026
The vulnerability identified in USP Ultimate Screenshot Painter, specifically within version code 240213.009, represents a critical failure in access control mechanisms governing file system operations on Android devices. This flaw stems from an insecure configuration of permissions and intent filters that allow the application to accept content URIs provided by external or untrusted sources without adequate validation. In standard Android security models, applications are expected to operate within strict sandbox boundaries, ensuring that they can only read or write data explicitly granted through secure permission requests or properly scoped URI grants. However, in this instance, the application fails to enforce these restrictions when processing incoming content URIs, thereby creating a pathway for privilege escalation and unauthorized file system manipulation.
The technical core of this vulnerability lies in how the application handles input from external providers via ContentResolver operations. When an attacker supplies a crafted content URI, they can trick the application into performing write or move operations on files located within another user's private storage directory. This behavior violates the fundamental principle of least privilege and isolation that defines mobile operating system security architectures. By exploiting this misconfiguration, an unauthorized actor does not need to bypass complex cryptographic protections or exploit kernel-level flaws; instead, they leverage a logic error in how the application interprets and executes file operations based on user-supplied input vectors. This type of flaw is commonly categorized under CWE-284 Improper Access Control, as it involves failing to restrict access to resources for unauthorized actors.
The operational impact of this vulnerability is significant, particularly regarding data integrity and confidentiality within a multi-user or shared-device environment. An attacker who can move or overwrite files in another user's private storage could potentially delete critical application data, corrupt configuration files, or replace legitimate assets with malicious counterparts. In scenarios where the targeted files contain sensitive personal information, such as photos, documents, or authentication tokens stored locally, this leads to a direct compromise of confidentiality and integrity. Furthermore, if the overwritten file is executed by another process or service associated with the victim user's account, it could lead to further code execution vulnerabilities, effectively turning a simple file manipulation flaw into a broader system compromise vector.
From an offensive security perspective, this vulnerability aligns closely with techniques observed in the MITRE ATT&CK framework for mobile platforms, specifically those related to persistence and privilege escalation through local file modifications. The ability to manipulate files outside of one's own sandbox allows attackers to establish footholds or disrupt service availability without triggering standard intrusion detection mechanisms that focus on network-based anomalies. This makes the vulnerability particularly dangerous in enterprise environments where device management policies might rely on the assumption that application sandboxes are impenetrable boundaries for lateral movement between user accounts.
Mitigation strategies must address both immediate remediation and long-term architectural improvements. The most effective solution is to update the application to a patched version where developers have implemented strict validation of incoming content URIs, ensuring they point only to resources within the app's own private storage or explicitly granted shared directories. Developers should also enforce read-only permissions for external inputs unless write access is absolutely necessary and has been verified through secure grant mechanisms provided by the Android framework. Additionally, implementing Content Provider security best practices, such as using FLAG_GRANT_READ_URI_PERMISSION appropriately and avoiding broad intent filters that accept arbitrary data types, will reduce the attack surface. For end-users, maintaining up-to-date software versions and restricting app permissions to only those strictly necessary for functionality are essential defensive measures against this class of insecure permission vulnerabilities.