CVE-2026-78071 in DP Calendar Extension
Summary
by MITRE • 08/28/2026
Joomla Extension - digital-peak.com - Authenticated, privileged stored XSS in DP Calendar 7.0.0 - 10.11.2 - Location title is rendered in data attribute without escaping leads to XSS, needs create permission in DPCalendar.
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Analysis
by VulDB Data Team • 08/28/2026
The vulnerability identified within the DP Calendar extension for Joomla versions ranging from 7.0.0 through 10.11.2 represents a significant security risk classified as an authenticated stored cross-site scripting flaw. This specific weakness arises from improper neutralization of user input before it is placed into data attributes, which are often consumed by JavaScript code during runtime. The core technical failure lies in the handling of the location title field within the calendar interface. When an administrator or a user with create permissions inputs text for this field, the system fails to apply adequate output encoding or sanitization mechanisms prior to rendering the value inside HTML data attributes. This lack of escaping allows malicious scripts embedded within the input string to persist in the database and subsequently execute when other users view the affected calendar entries.
From an architectural perspective, this vulnerability aligns with CWE-83, which defines Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS). The specific vector involves data attributes rather than direct innerHTML injection, but modern browsers interpret JavaScript within certain attribute contexts similarly to standard script execution if the context allows for event handlers or protocol-based injections. Because the input is stored server-side and served back to clients without proper validation, it constitutes a Stored Cross-Site Scripting attack as defined by CWE-79. This persistence distinguishes it from reflected XSS attacks, where malicious payloads are typically contained within a single HTTP request response cycle. The attacker does not need to trick a user into clicking a specially crafted link; instead, the payload is automatically executed whenever the compromised calendar event is rendered in any browser session accessing that data.
The operational impact of this vulnerability is severe due to its authenticated and privileged nature. An adversary must possess valid credentials with at least create permissions for DPCalendar events to exploit this flaw. Once access is granted, the attacker can inject arbitrary JavaScript code into the location title field. This capability enables a wide range of malicious activities including session hijacking through cookie theft, credential harvesting via fake login forms injected into the page context, and defacement of the application interface. Furthermore, because the script executes in the context of the victim user's active session with elevated privileges if they are an administrator, it can lead to full account compromise or further lateral movement within the Joomla environment. The attack effectively bypasses same-origin policy protections since the malicious code runs as part of the legitimate domain’s content.
In terms of threat modeling and adversary behavior, this vulnerability maps directly to MITRE ATT&CK technique T1059.007, which covers JavaScript execution in web browsers. It also relates to T1189 Drive-by Compromise if used for initial access via phishing links that lead to the vulnerable calendar view, although the stored nature makes it more akin to persistent delivery mechanisms. The exploitation chain typically involves creating a malicious event with a crafted location title containing script tags or event handler attributes such as onmouseover or onload payloads designed to exfiltrate session cookies or perform actions on behalf of the victim user. This persistence ensures that every subsequent view of the calendar data serves as an attack vector, amplifying the blast radius significantly compared to transient vulnerabilities.
Mitigation strategies must address both immediate remediation and long-term defensive posture improvements. The primary solution is for extension developers to apply strict output encoding when rendering the location title in HTML contexts, specifically ensuring that special characters are escaped before being placed into data attributes or any other DOM element. Implementing a Content Security Policy (CSP) with directives such as script-src 'self' can significantly mitigate the impact by preventing the execution of inline scripts and unauthorized external sources, thereby neutralizing many XSS payloads even if they are successfully injected. Administrators should immediately update to patched versions of DP Calendar once available from digital-peak.com. In the interim, restricting user permissions to only those absolutely necessary for their role reduces the attack surface by limiting who can create events with potentially malicious content. Regular security audits and input validation checks on all user-supplied data fields are essential practices to prevent similar vulnerabilities in web applications built on Joomla or other CMS platforms.