CVE-2026-101270 in pretix
Summary
by MITRE • 09/29/2026
Malicious HTML content could be injected into the help texts of various fields with organizer permissions.
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Analysis
by VulDB Data Team • 09/29/2026
The vulnerability described represents a classic Stored Cross-Site Scripting (XSS) flaw, specifically targeting administrative or organizational interfaces where users possess elevated privileges such as organizer permissions. In this scenario, an attacker who has been granted access to manage event details, user profiles, or other structured data fields can inject malicious HTML and JavaScript code into the help text sections of various input fields. Unlike reflected XSS, which requires tricking a victim into clicking a crafted link, stored XSS persists on the target server because the injected script is saved in the application's database alongside legitimate content. When any user subsequently views or interacts with these affected fields, the browser retrieves and executes the malicious code within the context of the vulnerable web application. This persistence makes the vulnerability particularly dangerous as it can affect multiple users over an extended period without further action from the attacker.
From a technical perspective, this flaw stems from insufficient input validation and output encoding mechanisms within the web application's backend logic. The system likely fails to sanitize special characters such as angle brackets, quotes, and ampersands when processing help text inputs, allowing raw HTML tags like script elements or event handlers on attributes to be rendered directly in the browser. Furthermore, if the content type is not explicitly set to plain text by the server before being sent to the client, modern browsers will interpret embedded scripts as executable code rather than static data. This lack of proper context-aware encoding allows attackers to bypass basic filters and execute arbitrary JavaScript commands within the user's session environment. The presence of organizer permissions exacerbates the risk because these users often have access to sensitive operational data or administrative functions that can be manipulated through script execution, potentially leading to privilege escalation if combined with other vulnerabilities like Cross-Site Request Forgery (CSRF).
The operational impact of this vulnerability is severe and multifaceted. Once executed in a victim's browser, the malicious script operates within the same origin policy as the legitimate application, granting it full access to cookies, session tokens, local storage, and DOM elements. Attackers can steal sensitive authentication credentials by exfiltrating session IDs to their own servers, effectively hijacking user accounts without needing passwords. Additionally, they can perform actions on behalf of the victim, such as modifying event settings, deleting data, or inviting unauthorized users, thereby compromising the integrity of the platform's operations. In environments where organizer permissions allow for financial transactions or sensitive communication management, this could lead to significant reputational damage and direct financial loss. The persistence of the payload means that every new user accessing the affected pages becomes a potential victim until the malicious content is manually removed from the database by an administrator who may not be aware of its presence due to obfuscation techniques used in the injection.
To mitigate this vulnerability, developers must implement strict input validation and output encoding strategies aligned with industry standards such as CWE-79 (Improper Neutralization of Input During Web Page Generation). All user-supplied data intended for display in HTML contexts should be encoded using appropriate libraries that handle character escaping based on the specific context within the DOM structure. Implementing a Content Security Policy (CSP) is also critical, as it restricts the sources from which scripts can be loaded and executed, thereby neutralizing many XSS attacks even if they are successfully injected into the page. Additionally, setting session cookies with the HttpOnly flag prevents client-side scripts from accessing sensitive cookie data, limiting the potential damage of a successful exploitation attempt. Regular security audits and static code analysis tools should be employed to detect such injection points early in the development lifecycle, ensuring that only sanitized and validated content is persisted in the database and rendered safely to end-users.