CVE-2019-8939 in Tautulli
Summary
by MITRE
data/interfaces/default/history.html in Tautulli 2.1.26 has XSS via a crafted Plex username that is mishandled when constructing the History page.
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Analysis
by VulDB Data Team • 07/11/2023
The vulnerability identified as CVE-2019-8939 affects Tautulli version 2.1.26 and represents a cross-site scripting flaw within the history page functionality. This issue stems from improper handling of user input when constructing the history interface, specifically targeting the Plex username parameter that is used in the data/interfaces/default/history.html file. The flaw allows attackers to inject malicious scripts through crafted usernames that are then executed in the context of other users' browsers when they view the history page.
The technical implementation of this vulnerability involves the web application's failure to properly sanitize or escape user-supplied data before incorporating it into dynamic HTML content. When Tautulli processes Plex usernames for display in the history interface, it does not adequately validate or encode the input, creating an opening for attackers to inject malicious JavaScript code. This type of vulnerability falls under CWE-79 which specifically addresses cross-site scripting vulnerabilities, where untrusted data is incorporated into web pages without proper validation or encoding. The vulnerability is particularly concerning as it operates at the user interface level where legitimate users interact with the application's history tracking features.
The operational impact of this vulnerability extends beyond simple script execution, as it provides attackers with the ability to perform actions on behalf of authenticated users within the application's context. An attacker could potentially steal session cookies, redirect users to malicious sites, or perform unauthorized actions within Tautulli's interface. The attack vector is particularly insidious because it requires minimal privileges to exploit, as the malicious input is processed through normal user interactions rather than requiring administrative access. This vulnerability aligns with ATT&CK technique T1566.001 which covers spearphishing with malicious attachments, though in this case the attack vector is through crafted user input rather than email attachments. The affected Tautulli application's history page serves as the attack surface where malicious script injection can occur when users view their media history records.
Mitigation strategies for CVE-2019-8939 should focus on implementing proper input validation and output encoding practices throughout the Tautulli application. The most effective remediation involves sanitizing all user-supplied data before incorporating it into HTML content, particularly within dynamic interfaces. This includes implementing proper HTML escaping mechanisms for all variables rendered in the history.html template, ensuring that special characters are properly encoded to prevent script execution. Organizations should also consider implementing Content Security Policy headers to limit the execution of inline scripts and restrict external resource loading. Additionally, upgrading to Tautulli versions that have addressed this vulnerability is crucial, as the issue was resolved in subsequent releases through improved input sanitization routines. The fix should include comprehensive testing of user input handling within all interface components, particularly those that display user-generated content such as usernames, titles, and descriptions. Security teams should also implement regular vulnerability scanning and input validation testing to prevent similar issues from emerging in other application components.