CVE-2026-78741 in Silverpeas
Summary
by MITRE • 09/09/2026
Silverpeas Core <=6.4.6 is vulnerable to Cross Site Scripting (XSS) in the wysiwyg-CKEditor image upload feature.
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Analysis
by VulDB Data Team • 09/09/2026
The vulnerability identified in Silverpeas Core versions up to 6.4.6 represents a significant security flaw within its content management and document handling subsystems, specifically targeting the integration of the CKEditor WYSIWYG editor for image uploads. This Cross-Site Scripting (XSS) issue arises from insufficient input validation and sanitization mechanisms when processing user-supplied data during the file upload process. When an authenticated user interacts with the rich text editing interface to insert or replace images, the application fails to adequately sanitize metadata associated with the uploaded files or improperly handles attributes within the HTML content generated by CKEditor. This allows attackers to inject malicious JavaScript payloads that are subsequently stored on the server and executed in the context of other users' browsers when they view the affected document or page.
From a technical perspective, this flaw is categorized under CWE-79, which defines Improper Neutralization of Input During Web Page Generation commonly known as Cross-site Scripting. The specific vector often involves reflected or stored XSS depending on whether the malicious script is executed immediately upon request processing or persisted in the database for later retrieval. In the context of Silverpeas, the persistence aspect makes this particularly dangerous because it transforms a single interaction into a persistent threat against all users with access to the compromised content. The CKEditor component, while robust for general text editing, can be manipulated if the backend does not strictly enforce allowlists on HTML tags and attributes or fails to encode special characters in user inputs before rendering them back to the client side.
The operational impact of this vulnerability is severe due to its potential to facilitate account hijacking and session manipulation. An attacker who successfully exploits this flaw can execute arbitrary JavaScript code within the victim's browser, effectively gaining control over the security context of Silverpeas for that user. This capability allows the extraction of sensitive information such as session cookies, authentication tokens, or personally identifiable data stored in local storage. Furthermore, the attacker could perform actions on behalf of the victim without their knowledge, including modifying content, deleting documents, or initiating requests to administrative endpoints if the compromised account possesses elevated privileges. In enterprise environments where Silverpeas is used for collaborative document management, this undermines the integrity and confidentiality of shared resources.
This vulnerability aligns with several techniques in the MITRE ATT&CK framework, particularly T1059 which covers Command and Scripting Interpreter execution via browser-based scripts, and T1213 concerning Data from Information Repositories if sensitive data is exfiltrated through this vector. The exploitation typically requires initial access to a valid user account with permissions to use the WYSIWYG editor, meaning it is not an unauthenticated remote code execution but rather an authenticated privilege escalation or session hijacking risk. Defense in depth strategies are essential here since client-side protections alone are insufficient against determined attackers who can bypass browser security features if they control the script context.
Mitigation efforts should prioritize immediate patching to version 6.4.7 or later where these input validation issues have been addressed by the vendor. In environments where upgrading is not immediately feasible, administrators should implement strict Content Security Policy headers that restrict inline script execution and limit sources from which scripts can be loaded. Additionally, enabling advanced sanitization filters on the server side to strip dangerous HTML tags such as script, object, or embed during file upload processing can reduce the attack surface. Regular security audits of third-party components like CKEditor are also recommended to ensure that integration points remain secure against evolving web exploitation techniques.