CVE-2025-46383 in Emby
Summary
by MITRE • 07/20/2025
CWE-79 Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting')
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Analysis
by VulDB Data Team • 07/20/2025
This vulnerability represents a classic cross-site scripting flaw that allows attackers to inject malicious scripts into web pages viewed by other users. The issue stems from inadequate input validation and output encoding mechanisms within web applications that process user-supplied data for dynamic content generation. When user input is directly incorporated into web page output without proper sanitization or encoding, it creates an opening for attackers to execute arbitrary JavaScript code in the context of other users' browsers.
The technical implementation of this vulnerability typically occurs when applications fail to properly neutralize special characters in user input before rendering it in HTML contexts. Attackers can exploit this weakness by submitting malicious payloads containing script tags, event handlers, or other JavaScript constructs that get executed when the compromised page loads. The vulnerability exists across multiple input vectors including form fields, URL parameters, cookies, and API responses that are subsequently rendered in web interfaces. This flaw directly maps to CWE-79 which categorizes improper neutralization of input during web page generation as a fundamental web security weakness that enables persistent and reflected XSS attacks.
From an operational perspective, the impact of this vulnerability can be severe and far-reaching. An attacker who successfully exploits this XSS flaw can hijack user sessions, steal sensitive authentication tokens, perform unauthorized actions on behalf of victims, and potentially gain access to confidential data. The attack surface extends beyond simple script execution to include session manipulation, data exfiltration, and privilege escalation opportunities. Depending on the application's functionality, attackers might be able to read or modify user data, access administrative functions, or redirect users to malicious sites. The vulnerability can persist across multiple user sessions and may require application restarts to fully remediate, making it particularly dangerous in enterprise environments where user trust and data integrity are paramount.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term architectural improvements. The primary defense involves implementing comprehensive input validation and output encoding mechanisms that properly escape special characters before rendering user data in web contexts. Applications should employ context-aware encoding techniques that adapt to different output contexts including HTML, JavaScript, CSS, and URL parameters. Security measures should include the implementation of Content Security Policy headers, proper use of secure HTTP-only cookies, and regular security testing including automated scanning and manual penetration testing. Organizations must also establish secure coding practices and conduct regular security training for development teams to prevent similar vulnerabilities from being introduced in future releases. The remediation approach aligns with ATT&CK technique T1059.007 for command and scripting interpreter and T1566.001 for valid accounts, as attackers often leverage XSS to escalate privileges and maintain persistence through compromised user sessions.