CVE-2024-40785: Apple iPhone OS XSS Vulnerability

CVE-2024-40785 Overview

CVE-2024-40785 is a Cross-Site Scripting (XSS) vulnerability affecting Apple's WebKit browser engine across multiple Apple platforms. The vulnerability exists due to insufficient input validation when processing web content. An attacker can craft malicious web content that, when processed by an affected application, executes arbitrary scripts in the context of a victim's browsing session.

This vulnerability affects a wide range of Apple products including iOS, iPadOS, Safari, watchOS, tvOS, visionOS, and macOS Sonoma. Apple addressed this issue with improved checks in multiple security updates released in July 2024.

Critical Impact

Processing maliciously crafted web content may lead to a cross-site scripting attack, potentially allowing attackers to steal sensitive information, hijack user sessions, or perform actions on behalf of users.

Affected Products

• Apple iOS (versions prior to 16.7.9 and 17.6)
• Apple iPadOS (versions prior to 16.7.9 and 17.6)
• Apple Safari (versions prior to 17.6)
• Apple watchOS (versions prior to 10.6)
• Apple tvOS (versions prior to 17.6)
• Apple visionOS (versions prior to 1.3)
• Apple macOS Sonoma (versions prior to 14.6)

Discovery Timeline

• July 29, 2024 - CVE-2024-40785 published to NVD
• November 4, 2025 - Last updated in NVD database

Technical Details for CVE-2024-40785

Vulnerability Analysis

CVE-2024-40785 is classified as CWE-79 (Improper Neutralization of Input During Web Page Generation), commonly known as Cross-Site Scripting. The vulnerability resides in Apple's WebKit engine, which is the core rendering engine used by Safari and other Apple applications that display web content.

The flaw stems from inadequate validation checks when the WebKit engine processes certain types of web content. When a user visits a malicious webpage or processes attacker-controlled web content, the vulnerability allows for the execution of arbitrary JavaScript in the security context of the target origin. This can enable attackers to access cookies, session tokens, and other sensitive data stored in the browser, as well as perform actions impersonating the victim user.

The network-based attack vector requires user interaction, as the victim must navigate to or be redirected to malicious content. The vulnerability has a changed scope, meaning successful exploitation can impact resources beyond the vulnerable component's security scope.

Root Cause

The root cause of CVE-2024-40785 lies in insufficient input validation within WebKit's content processing routines. When handling specific web content structures, WebKit failed to properly sanitize or escape user-controlled input before rendering it in the browser context. This oversight allows attackers to inject malicious scripts that execute when the content is processed.

Apple addressed this vulnerability by implementing improved checks in the content processing pipeline, ensuring that potentially dangerous input is properly validated and neutralized before being rendered.

Attack Vector

The attack vector for CVE-2024-40785 is network-based and requires user interaction. An attacker would typically:

1. Craft malicious web content containing XSS payloads
2. Host this content on a malicious website or inject it into a legitimate site through other means
3. Lure the victim to visit the malicious page through phishing, social engineering, or malicious advertisements
4. When the victim's browser renders the content, the malicious scripts execute in the context of the vulnerable application

The attack does not require any privileges and can be executed against any user visiting the malicious content. Due to the changed scope characteristic, the attack can potentially affect cross-origin resources, making session hijacking and credential theft possible.

Detection Methods for CVE-2024-40785

Indicators of Compromise

• Unexpected JavaScript execution or browser behavior when visiting websites
• Suspicious network requests to unknown domains initiated by the browser
• Unusual cookie modifications or session token exfiltration attempts
• Browser console errors indicating script injection attempts

Detection Strategies

• Monitor web traffic for suspicious JavaScript payloads in HTTP responses
• Implement Content Security Policy (CSP) headers and monitor for violations
• Use browser-based XSS auditors and web application firewalls to detect injection attempts
• Review application logs for unusual cross-origin requests

Monitoring Recommendations

• Enable and monitor CSP violation reports for attempted script injections
• Implement network-level monitoring for connections to known malicious domains
• Deploy endpoint detection solutions capable of identifying WebKit exploitation attempts
• Regularly audit browser extensions and plugins that may interact with web content

How to Mitigate CVE-2024-40785

Immediate Actions Required

• Update all Apple devices to the latest patched versions immediately
• Ensure automatic updates are enabled for iOS, iPadOS, macOS, watchOS, tvOS, and visionOS
• Instruct users to avoid clicking links from untrusted sources until patches are applied
• Review and restrict access to sensitive web applications from unpatched devices

Patch Information

Apple has released security updates addressing CVE-2024-40785 across all affected platforms. Users and administrators should update to the following versions or later:

Debian has also released updates for WebKitGTK addressing this vulnerability. See the Debian LTS Announcement for details.

Workarounds

• Implement strict Content Security Policy (CSP) headers on web applications to mitigate XSS impact
• Use browser isolation technologies to contain potential exploits
• Restrict JavaScript execution on sensitive sites using browser extensions until patches are applied
• Deploy web application firewalls with XSS detection rules at the network perimeter

# Example CSP header configuration for Apache
# Add to httpd.conf or .htaccess
Header set Content-Security-Policy "default-src 'self'; script-src 'self'; style-src 'self' 'unsafe-inline'; img-src 'self' data:; frame-ancestors 'self';"