CVE-2026-105409 in Tuleap
Summary
by MITRE • 10/12/2026
A Stored Cross-site Scripting (XSS) vulnerability affecting Tuleap Enterprise Edition from 17.0 through 17.5 could allow an attacker to execute arbitrary script code in user's browser session.
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Analysis
by VulDB Data Team • 10/12/2026
The identified security flaw represents a classic instance of stored cross-site scripting, specifically categorized under CWE-79 within the Common Weakness Enumeration framework. This vulnerability impacts Tuleap Enterprise Edition versions ranging from 17.0 through 17.5 and stems from insufficient sanitization or validation of user-supplied input before it is persistently stored on the server side. Unlike reflected XSS, where malicious scripts are executed immediately via a crafted link, this variant allows an attacker to embed executable JavaScript code into data fields that are subsequently retrieved and rendered by other users' browsers without further modification. The persistence of the payload means that every time a victim accesses the compromised page or feature containing the tainted data, the browser interprets and executes the injected script as part of the legitimate webpage content.
From an operational perspective, this vulnerability poses significant risks to both individual user sessions and organizational security postures. An attacker can leverage this flaw to perform session hijacking by stealing authentication cookies or tokens, thereby gaining unauthorized access to a victim's account with all associated privileges. Furthermore, the malicious script can manipulate the Document Object Model of the affected page, potentially leading to defacement, redirection to phishing sites designed to harvest credentials, or automated actions performed on behalf of the user without their knowledge. In enterprise environments using Tuleap for project management and collaboration, such an attack could facilitate broader lateral movement if combined with other vulnerabilities, as compromised accounts often serve as entry points into internal networks.
The technical mechanism typically involves a failure in input validation logic where special characters are not properly escaped or encoded before being written to the database or file system. When the application later retrieves this data for display, it fails to apply appropriate output encoding strategies such as HTML entity encoding, which would neutralize script tags and event handlers. This oversight allows raw JavaScript code to pass through the rendering pipeline intact. The impact is exacerbated by the fact that stored XSS payloads do not require social engineering tactics like tricking a user into clicking a specific link; instead, they activate automatically upon viewing infected content, increasing the likelihood of successful exploitation across multiple users who interact with the affected application features.
Mitigation strategies must address both immediate remediation and long-term defensive posture improvements. The primary corrective action is to apply vendor-provided patches or updates that resolve this vulnerability in Tuleap versions 17.0 through 17.5, ensuring that input validation routines are hardened against injection attacks. Developers should implement strict allow-listing for permitted characters in user inputs and enforce robust output encoding based on the context of data insertion, such as HTML body, attribute values, or JavaScript blocks. Additionally, deploying a Web Application Firewall can provide an additional layer of defense by filtering out malicious payloads before they reach the application logic. Regular security audits and code reviews focusing on input handling practices are essential to prevent recurrence.
In terms of threat intelligence alignment, this vulnerability maps directly to MITRE ATT&CK technique T1059.007, which covers JavaScript execution within web browsers. Understanding this mapping helps organizations prioritize response efforts based on the specific tactics an adversary might employ during a cyber attack lifecycle. By addressing the root cause through secure coding practices and maintaining up-to-date software versions, administrators can significantly reduce the risk surface associated with stored XSS attacks in collaborative platforms like Tuleap Enterprise Edition.