CVE-2026-30828 in Wallos
Summary
by MITRE • 03/07/2026
Wallos is an open-source, self-hostable personal subscription tracker. Prior to version 4.6.2, the url parameter can be used to retrieve local system files. This issue has been patched in version 4.6.2.
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Analysis
by VulDB Data Team • 03/12/2026
The vulnerability identified as CVE-2026-30828 affects Wallos, an open-source personal subscription tracking application designed for self-hosting environments. This application allows users to manage their subscription expenses by tracking various services they pay for, making it a potentially attractive target for attackers seeking to compromise user data or system integrity. The vulnerability stems from improper input validation within the application's handling of URL parameters, specifically exposing a path traversal flaw that enables unauthorized access to local system files. This issue represents a critical security weakness in the application's architecture, as it directly enables attackers to bypass normal access controls and retrieve sensitive information from the underlying operating system.
The technical flaw manifests through the application's insufficient sanitization of the url parameter, which allows malicious actors to manipulate input values to traverse the file system hierarchy. This vulnerability can be exploited by constructing specially crafted URLs that include directory traversal sequences such as ../ or ..\, enabling access to files outside the intended web root directory. The flaw essentially creates a path traversal vulnerability that falls under the CWE-22 category, which specifically addresses improper limitation of a pathname to a restricted directory, commonly known as directory traversal or path traversal attacks. Attackers can leverage this weakness to access configuration files, database files, system logs, or other sensitive data that should remain protected from unauthorized access.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can lead to complete system compromise when combined with other exploitation techniques. An attacker who successfully exploits this vulnerability can gain access to sensitive user data including subscription details, payment information, and potentially system credentials stored within the application's configuration files. The self-hosted nature of Wallos means that organizations or individuals running this application on their own servers are directly exposed to this risk, with no centralized security team to provide immediate mitigation. This vulnerability also aligns with ATT&CK technique T1083 (File and Directory Discovery) and T1566 (Phishing), as attackers can use the information gathered through path traversal to further their attacks or craft more sophisticated social engineering campaigns against users.
Mitigation strategies for CVE-2026-30828 focus primarily on upgrading to version 4.6.2 or later, which contains the necessary patches to address the path traversal vulnerability. System administrators should immediately implement this update across all instances of the application in their environment, particularly in production systems where sensitive subscription data is stored. Additional defensive measures include implementing proper input validation at the application level, using secure coding practices that prevent directory traversal attacks, and applying principle of least privilege access controls to limit the application's file system access. Organizations should also consider implementing web application firewalls to detect and block suspicious URL patterns, as well as conducting regular security assessments to identify similar vulnerabilities in other applications within their infrastructure. The fix in version 4.6.2 demonstrates the importance of maintaining up-to-date software and the critical need for proper input validation in web applications that handle user-supplied data.