CVE-2025-24208 Overview
CVE-2025-24208 is a cross-site scripting (XSS) vulnerability [CWE-79] affecting Apple Safari, iOS, and iPadOS. The flaw stems from a permissions issue in how the browser handles iframes. Loading a malicious iframe can lead to a cross-site scripting attack against the user. Apple addressed the issue by adding additional restrictions in Safari 18.4, iOS 18.4, and iPadOS 18.4. Exploitation requires user interaction, such as visiting an attacker-controlled page. The vulnerability affects the WebKit engine used across Apple platforms.
Critical Impact
Successful exploitation allows attackers to execute arbitrary script in the context of another origin, enabling session theft, credential harvesting, and content manipulation across trusted sites.
Affected Products
- Apple Safari (versions prior to 18.4)
- Apple iOS (versions prior to 18.4)
- Apple iPadOS (versions prior to 18.4)
Discovery Timeline
- 2025-03-31 - CVE-2025-24208 published to the National Vulnerability Database (NVD)
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-24208
Vulnerability Analysis
CVE-2025-24208 is classified as an Improper Neutralization of Input During Web Page Generation [CWE-79], commonly known as cross-site scripting. The root cause is a permissions issue in Safari's handling of iframe content. When a page loads a malicious iframe, insufficient origin restrictions allow script from the framed context to affect the parent or sibling document context. This scope-change behavior is reflected in the changed scope component of the vulnerability, meaning code executed in one security context can impact another. The result is client-side script injection against sites the victim visits.
Root Cause
The underlying defect is inadequate enforcement of cross-origin permissions when rendering iframes within Safari's WebKit engine. Apple's advisory describes the fix as adding additional restrictions, indicating the pre-patch code path did not correctly isolate iframe-loaded resources from the embedding document. The lack of proper isolation permits script execution outside the intended origin boundary.
Attack Vector
Exploitation occurs over the network and requires user interaction. An attacker hosts a crafted web page containing a malicious iframe, then lures a Safari, iOS, or iPadOS user into visiting the page. Once loaded, the malicious frame executes JavaScript that can read or modify data within another site's context. Typical attacker objectives include stealing session cookies, exfiltrating form input, and defacing rendered content. No authentication is required, and the attacker never needs local access to the target device. See the Apple Support Document #122371 and Apple Support Document #122379 for vendor technical details.
No verified public proof-of-concept code is available at the time of publication. Refer to the Full Disclosure Mailing List Post for additional context.
Detection Methods for CVE-2025-24208
Indicators of Compromise
- Safari or WebKit-based browser processes rendering pages that inject unexpected <iframe> elements referencing attacker-controlled domains.
- Outbound network requests from user devices to newly registered or low-reputation domains immediately after browsing activity.
- Unusual JavaScript execution artifacts in browser telemetry, such as cross-origin postMessage or DOM access errors preceding data exfiltration.
Detection Strategies
- Inspect web proxy and DNS logs for high-risk domains loaded within iframes on otherwise trusted sites.
- Deploy Content Security Policy (CSP) reporting endpoints on managed web properties to capture attempts to load unauthorized frame sources.
- Correlate browser version telemetry against Safari, iOS, and iPadOS builds earlier than 18.4 to identify exposed assets.
Monitoring Recommendations
- Monitor mobile device management (MDM) inventory for iOS and iPadOS endpoints running versions below 18.4.
- Track Safari version reporting on macOS fleets and alert on installations prior to Safari 18.4.
- Review authentication logs for anomalous session reuse patterns that could indicate stolen cookies obtained through XSS.
How to Mitigate CVE-2025-24208
Immediate Actions Required
- Update Safari to version 18.4 on all supported macOS installations.
- Upgrade iOS and iPadOS devices to version 18.4 through Software Update or MDM-enforced policies.
- Prioritize patching for users who handle sensitive credentials or access high-value web applications.
Patch Information
Apple resolved CVE-2025-24208 by adding additional permission restrictions in Safari 18.4, iOS 18.4, and iPadOS 18.4. Full details are available in Apple Support Document #122371 and Apple Support Document #122379. Downstream distributions have also shipped fixes, including the Debian LTS Announcement covering WebKit-based components.
Workarounds
- Restrict browsing to trusted sites until patches are applied, particularly on unpatched iOS and iPadOS devices.
- Enforce strict Content Security Policy frame-src and frame-ancestors directives on internally managed web applications to limit iframe-based attack surface.
- Use MDM configuration profiles to block installation of legacy Safari builds on managed Apple endpoints.
# Verify Safari version on macOS
defaults read /Applications/Safari.app/Contents/Info.plist CFBundleShortVersionString
# Example strict CSP header limiting iframe sources on managed web apps
# Content-Security-Policy: default-src 'self'; frame-src 'self' https://trusted.example.com; frame-ancestors 'self'
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
