CVE-2026-59668 in Repasat
Summary
by MITRE • 10/02/2026
Cross-Site Scripting vulnerability in the Repasat application. Successful exploitation of this vulnerability could allow an attacker to trick a user into executing arbitrary code in the victim’s browser. The “nomTamano” parameter is affected – endpoint “/es/companysizebills/store”.
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Analysis
by VulDB Data Team • 10/02/2026
The identified Cross-Site Scripting (XSS) vulnerability within the Repasat application represents a significant security risk, specifically located at the /es/companysizebills/store endpoint. This flaw stems from insufficient input validation and sanitization mechanisms applied to the nomTamano parameter. When user-supplied data is processed by the server or reflected back in the response without proper encoding, it allows malicious actors to inject executable scripts into web pages viewed by other users. The core technical failure lies in the application's inability to distinguish between legitimate data input and hostile script payloads, thereby violating fundamental principles of secure coding practices that mandate strict type checking and output escaping for all dynamic content.
Exploitation of this vulnerability enables an attacker to execute arbitrary JavaScript code within the context of the victim’s browser session. This capability is particularly dangerous because it operates under the same origin policy as the legitimate application, granting the injected script full access to cookies, local storage, session tokens, and other sensitive data associated with the user's account on Repasat. By crafting a malicious link or embedding the payload in a phishing email, an attacker can trick a targeted user into triggering the execution of this code simply by visiting a compromised page or clicking a manipulated URL. The impact extends beyond simple defacement; it facilitates session hijacking, where the attacker assumes the identity of the victim to perform unauthorized actions such as modifying company size bills, exfiltrating sensitive corporate data, or redirecting users to malicious sites designed for further exploitation.
From an industry standards perspective, this vulnerability aligns with CWE-79: Improper Neutralization of Input During Web Page Generation, commonly known as Cross-Site Scripting. The specific nature of the flaw suggests a reflection-based approach if the payload is immediately returned in the HTTP response without being stored on the server, although persistent storage cannot be ruled out without further analysis. In terms of offensive security frameworks, this attack vector maps directly to MITRE ATT&CK technique T1059.007: Command and Scripting Interpreter: JavaScript, which falls under the broader category of Execution (TA0002). The attacker leverages the browser's native scripting engine to achieve code execution, bypassing traditional network-level security controls that do not inspect application-layer content for script injection patterns.
To mitigate this vulnerability, immediate remediation efforts must focus on implementing robust input validation and output encoding strategies. Developers should enforce strict allow-lists for the nomTamano parameter, ensuring it only accepts expected data types such as integers or specific alphanumeric strings, rejecting any input containing special characters like angle brackets, quotes, or ampersands that are commonly used in script injection attempts. Furthermore, all user-supplied data must be contextually encoded before being rendered in HTML responses. This includes encoding for HTML entities to prevent the browser from interpreting injected text as executable markup. Implementing Content Security Policy (CSP) headers can also serve as an effective defense-in-depth measure by restricting the sources from which scripts are allowed to load and execute, thereby neutralizing many XSS attacks even if input validation fails. Regular security testing, including both static application security testing and dynamic penetration tests focusing on parameter manipulation, is essential to ensure that such flaws do not persist in future releases of the Repasat platform.