CVE-2026-59670 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 “nomListaValidacion” parameter is affected – endpoint “/es/validationslists/assignList/Employee/45659”.
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Analysis
by VulDB Data Team • 10/02/2026
The Repasat application contains a Cross-Site Scripting vulnerability within its validation list assignment functionality, specifically targeting the nomListaValidacion parameter at the /es/validationsLists/assignList/Employee endpoint. This flaw represents a classic instance of reflected or stored input sanitization failure where user-supplied data is incorporated into web page content without adequate verification or encoding of dangerous characters. The vulnerability arises because the application fails to properly neutralize special characters such as angle brackets, quotes, and ampersands within the specified parameter before rendering it in the browser context. This lack of rigorous output encoding allows an attacker to inject malicious script payloads directly into the response stream returned by the server.
From a technical perspective, this vulnerability falls under CWE-79: Improper Neutralization of Input During Web Page Generation, commonly known as Cross-Site Scripting or XSS. The specific vector involves the nomListaValidacion parameter which is likely used to display validation list names or configurations in the user interface. When an attacker crafts a request with malicious JavaScript code embedded within this parameter value, the server processes it and returns it to the victim's browser without stripping out executable script tags or event handlers. Consequently, when the victim loads the affected page, their browser interprets the injected content as legitimate application code rather than data, leading to the execution of arbitrary scripts in the context of the vulnerable web application.
The operational impact of this vulnerability is significant due to its potential for session hijacking and credential theft. By exploiting this flaw, an attacker can execute JavaScript that accesses sensitive cookies containing session tokens, potentially allowing them to impersonate legitimate users and gain unauthorized access to their accounts. Furthermore, the attack vector enables phishing attacks where the malicious script can dynamically alter the appearance of the application to mimic login pages or other trusted interfaces, tricking victims into submitting credentials directly to the attacker's controlled server. This capability extends beyond simple defacement; it facilitates persistent data exfiltration and manipulation of user interactions within the Repasat environment, compromising both confidentiality and integrity of the system.
In terms of threat modeling, this vulnerability aligns with ATT&CK technique T1059.007: Command and Scripting Interpreter: JavaScript, which describes how attackers use scripting languages to execute commands or perform actions on behalf of a user within a web application context. The attack typically involves social engineering components where the attacker must trick a victim into clicking a malicious link containing the crafted payload in the nomListaValidacion parameter. Once executed, the script operates with the same privileges as the legitimate application code, bypassing many client-side security controls such as the Same-Origin Policy because it runs within the trusted domain of the Repasat application itself.
To mitigate this vulnerability, developers must implement strict input validation and output encoding strategies across all affected endpoints. Input validation should enforce a whitelist approach for the nomListaValidacion parameter, ensuring that only expected alphanumeric characters or specific safe symbols are accepted while rejecting any potentially dangerous content such as script tags, event handlers, or encoded HTML entities. More critically, output encoding must be applied consistently when rendering user-supplied data in HTML contexts. This involves converting special characters like less-than and greater-than signs into their corresponding HTML entity equivalents before they are written to the response body. Additionally, implementing Content Security Policy headers can provide a robust defense-in-depth layer by restricting the sources from which scripts can be loaded or executed, thereby mitigating the impact even if an injection attempt succeeds. Regular security testing including dynamic application security scanning and manual penetration testing should also be conducted to identify similar flaws in other parameters throughout the Repasat application architecture.