CVE-2026-78742 in Silverpeas
Summary
by MITRE • 09/09/2026
Silverpeas Core <=6.4.6 is vulnerable to Cross Site Scripting (XSS) via the Multimedia library application introduction.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 09/09/2026
The vulnerability identified in Silverpeas Core versions up to and including 6.4.6 represents a significant security flaw within its multimedia management subsystem, specifically affecting the introduction functionality of the Multimedia Library application. This Cross-Site Scripting (XSS) issue stems from insufficient input validation and sanitization mechanisms when processing user-supplied data intended for content descriptions or metadata fields. In typical web applications utilizing rich text editors or free-form text inputs, developers must ensure that special characters are properly encoded to prevent them from being interpreted as executable code by the browser. However, in this specific implementation of Silverpeas Core, the application fails to adequately neutralize script tags and other potentially malicious payloads before rendering them back to the user interface. This oversight allows an attacker who has access to create or modify content within the multimedia library to inject client-side scripts that will execute automatically when another user views the affected item.
From a technical perspective, this vulnerability is classified under CWE-79, which covers Improper Neutralization of Input During Web Page Generation commonly known as Cross-site Scripting. The attack vector typically involves an attacker crafting a malicious payload containing JavaScript code and embedding it within the introduction text or associated metadata of a multimedia file. When a victim with valid authentication credentials accesses this content through their web browser, the browser interprets the injected script as part of the page's legitimate source code. This execution occurs in the context of the Silverpeas application, granting the malicious script access to session cookies, local storage data, and other sensitive information associated with the user's active session. The flaw is particularly dangerous because it does not require complex exploitation techniques or external tools; a simple interaction such as clicking on a link or viewing an image can trigger the execution of the injected code if the victim has previously been tricked into submitting the malicious content.
The operational impact of this vulnerability extends beyond mere data leakage, potentially leading to complete account compromise and further lateral movement within the organization's network infrastructure. An attacker could utilize the executed script to perform actions on behalf of the victim without their knowledge or consent. This includes but is not limited to changing user settings, deleting content, adding new administrators, or exfiltrating sensitive documents stored in the multimedia library. Furthermore, if Silverpeas Core is integrated with other enterprise systems via single sign-on protocols or shared session tokens, the compromise could cascade into broader system breaches. The ability to execute arbitrary JavaScript also facilitates phishing attacks where the attacker can create a fake login page within the application's frame to steal credentials from unsuspecting users who believe they are interacting with legitimate Silverpeas functionality.
Mitigation strategies for this vulnerability involve both immediate remediation and long-term architectural improvements. For organizations currently running affected versions, the primary recommendation is to upgrade immediately to version 6.4.7 or later where these input validation issues have been addressed by the development team. If upgrading is not feasible in the short term, administrators should implement strict access controls to ensure that only trusted users with verified identities can create or modify multimedia content introductions. Additionally, deploying a Web Application Firewall (WAF) configured with rulesets designed to detect and block common XSS payloads such as script tags, event handlers like onerror or onload, and encoded JavaScript URIs can provide an additional layer of defense by intercepting malicious requests before they reach the application server.
To prevent similar vulnerabilities in future development cycles, it is essential to adopt a secure coding lifecycle that emphasizes input validation and output encoding. Developers should adhere to the principle of least privilege when handling user inputs and ensure that all data rendered back to the client is properly context-aware encoded based on where it appears within the HTML structure. Implementing Content Security Policy headers can also significantly mitigate the impact of successful XSS attacks by restricting the sources from which scripts are allowed to load, thereby preventing inline script execution even if an injection attempt succeeds. Regular security audits and penetration testing focused on web application vulnerabilities like those mapped in the MITRE ATT&CK framework under techniques such as T1059 Command and Scripting Interpreter can help identify these weaknesses before they are exploited by malicious actors. By combining technical fixes with robust operational practices, organizations can effectively reduce their attack surface and protect sensitive multimedia assets from unauthorized access and manipulation.