CVE-2024-41810: Twisted Web Framework XSS Vulnerability

CVE-2024-41810 Overview

CVE-2024-41810 is a Cross-Site Scripting (XSS) vulnerability affecting Twisted, an event-based framework for internet applications supporting Python 3.6+. The vulnerability exists within the twisted.web.util.redirectTo function, which contains an HTML injection flaw. When application code allows an attacker to control the redirect URL, this vulnerability enables Reflected Cross-Site Scripting (XSS) attacks through the redirect response HTML body.

Critical Impact

Attackers who can control redirect URLs in applications using Twisted can inject malicious scripts that execute in victims' browsers, potentially leading to session hijacking, credential theft, or unauthorized actions on behalf of authenticated users.

Affected Products

• Twisted (all versions prior to 24.7.0rc1)
• Python applications utilizing twisted.web.util.redirectTo function
• Web services built on the Twisted framework that implement redirect functionality

Discovery Timeline

• 2024-07-29 - CVE CVE-2024-41810 published to NVD
• 2025-11-03 - Last updated in NVD database

Technical Details for CVE-2024-41810

Vulnerability Analysis

This vulnerability arises from improper handling of user-controlled input within the twisted.web.util.redirectTo function. When a web application built on Twisted uses this function to perform HTTP redirects, the redirect URL is incorporated into an HTML response body. The function fails to properly sanitize or encode the URL parameter before embedding it in the HTML output, creating an HTML injection vector.

The network-based attack requires user interaction, as victims must click on or be redirected to a malicious URL. Once triggered, the injected script executes within the context of the vulnerable application's origin, allowing attackers to bypass same-origin policy protections. This can lead to theft of sensitive data including session cookies, authentication tokens, and personal information displayed on the page.

Root Cause

The root cause is insufficient output encoding in the twisted.web.util.redirectTo function. When constructing the HTML redirect response, the function directly incorporates the destination URL without properly escaping HTML special characters. This allows attackers to break out of the intended HTML context and inject arbitrary script content.

The vulnerability is classified as CWE-79 (Improper Neutralization of Input During Web Page Generation), commonly known as Cross-Site Scripting. The lack of proper contextual output encoding means that characters like <, >, ", and ' in attacker-controlled URLs can be interpreted as HTML markup rather than literal text.

Attack Vector

The attack requires an attacker to craft a malicious URL containing JavaScript payload embedded within the redirect destination parameter. When an application passes this attacker-controlled URL to the twisted.web.util.redirectTo function, the malicious script is reflected back to the user in the HTTP response body.

A typical exploitation scenario involves:

1. Attacker identifies an endpoint that uses redirectTo with user-controllable URL parameters
2. Attacker crafts a URL containing XSS payload (e.g., <script> tags or event handlers)
3. Attacker sends the malicious link to a victim via phishing, social engineering, or embedding it in a forum post
4. Victim clicks the link, triggering the redirect mechanism
5. The injected JavaScript executes in the victim's browser within the application's security context

For detailed technical information about this vulnerability, refer to the GitHub Security Advisory published by the Twisted maintainers.

Detection Methods for CVE-2024-41810

Indicators of Compromise

• Unusual URL patterns containing HTML/JavaScript payloads in redirect parameters
• HTTP requests with encoded script tags (%3Cscript%3E) in URL query strings
• Web application logs showing redirect requests with suspicious special characters
• Client-side JavaScript errors from unexpected script execution in redirect responses

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect XSS payloads in URL parameters
• Monitor web server access logs for requests containing encoded HTML/JavaScript patterns
• Deploy Content Security Policy (CSP) headers to detect and block inline script execution
• Use browser-based XSS auditing tools and security headers like X-XSS-Protection

Monitoring Recommendations

• Enable detailed logging for all redirect operations in Twisted-based applications
• Configure SIEM alerts for patterns matching common XSS payload signatures in web traffic
• Implement real-time monitoring of CSP violation reports to detect exploitation attempts
• Regularly scan application dependencies to identify vulnerable Twisted versions

How to Mitigate CVE-2024-41810

Immediate Actions Required

• Upgrade Twisted to version 24.7.0rc1 or later immediately
• Audit all application code that uses twisted.web.util.redirectTo with user-controlled input
• Implement input validation to restrict redirect URLs to trusted destinations only
• Deploy Content Security Policy headers to mitigate XSS impact as defense-in-depth

Patch Information

The vulnerability is fixed in Twisted version 24.7.0rc1. The patch, available in commit 046a164f89a0f08d3239ecebd750360f8914df33, implements proper HTML encoding for the redirect URL before it is embedded in the response body. Organizations should upgrade to the patched version through standard package management:

pip install --upgrade twisted>=24.7.0rc1

Additional vendor information is available in the Twisted Security Advisory. Debian users should also refer to the Debian LTS Announcement for distribution-specific guidance.

Workarounds

• Validate and sanitize all user input before passing to redirectTo function
• Implement an allowlist of permitted redirect destinations
• Use URL parsing to ensure redirect targets are within expected domains
• Apply manual HTML encoding to redirect URLs as a temporary measure until patching is possible

# Configuration example - verify installed Twisted version
pip show twisted | grep Version

# Upgrade to patched version
pip install --upgrade "twisted>=24.7.0"

# For requirements.txt, update the dependency
echo "twisted>=24.7.0" >> requirements.txt