CVE-2024-27838 Overview
CVE-2024-27838 is an information disclosure vulnerability affecting Apple Safari and multiple Apple operating systems. A maliciously crafted webpage can fingerprint the user, enabling tracking across browsing sessions without consent. Apple addressed the issue by adding additional logic to the affected component. The flaw impacts Safari, iOS, iPadOS, macOS Sonoma, tvOS, visionOS, and watchOS. The vulnerability is classified under [CWE-79] and carries a Network attack vector requiring user interaction. Apple published fixes across its ecosystem in May 2024, and the CVE was disclosed publicly in June 2024.
Critical Impact
A maliciously crafted webpage can fingerprint users across Safari and Apple operating systems, enabling covert tracking and profiling of victims who simply visit an attacker-controlled site.
Affected Products
- Apple Safari (prior to 17.5)
- Apple iOS and iPadOS (prior to 16.7.8 and 17.5)
- Apple macOS Sonoma (prior to 14.5), tvOS 17.5, visionOS 1.2, watchOS 10.5
Discovery Timeline
- 2024-06-10 - CVE-2024-27838 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2024-27838
Vulnerability Analysis
CVE-2024-27838 is an information disclosure flaw in Apple's WebKit-based browser stack. The vulnerability allows a maliciously crafted webpage to collect identifying characteristics from the browser environment. These characteristics can be combined into a stable fingerprint that follows users across sessions. Apple's fix introduces additional logic to the affected surface, narrowing the data available to untrusted web content.
The issue is tracked under [CWE-79] in NVD, though the practical impact is fingerprinting rather than script execution against another origin. The vulnerability requires the user to visit a page under attacker control. No credentials or prior access are required.
Root Cause
The root cause is insufficient isolation between web content and browser or system attributes exposed through Safari's rendering engine. Without the added logic, JavaScript running in a webpage could observe distinguishing behavior or attributes that uniquely identify a device or user. Apple did not publish detailed technical write-ups, and the vendor advisory only notes that additional logic was added to prevent the fingerprinting behavior.
Attack Vector
Exploitation occurs remotely over the network with user interaction. An attacker hosts a malicious webpage or injects content into a page a target visits. When the victim loads the page in a vulnerable version of Safari or an embedded WebKit view on iOS, iPadOS, macOS, tvOS, visionOS, or watchOS, the page can query the exposed attributes and construct a persistent user fingerprint. The attacker can then correlate the visitor across sites and sessions.
No verified proof-of-concept code has been published for CVE-2024-27838. Technical details are limited to Apple's advisories and the Full Disclosure post from June 2024.
Detection Methods for CVE-2024-27838
Indicators of Compromise
- Safari or WebKit clients still reporting build versions earlier than Safari 17.5, iOS/iPadOS 17.5 or 16.7.8, or macOS Sonoma 14.5 after the patch window
- Outbound web traffic to domains known to run fingerprinting scripts or advertising and tracking networks that correlate user identifiers
- Repeated visits from the same user to third-party analytics endpoints emitting high-entropy device attribute payloads
Detection Strategies
- Inventory browsers and OS builds across managed Apple devices and flag any versions older than the patched releases
- Monitor Mobile Device Management (MDM) compliance reports for iOS, iPadOS, macOS, tvOS, visionOS, and watchOS to confirm systems received the May 2024 security updates
- Correlate user-agent strings in web proxy or SIEM logs against the patched Safari versions to identify unpatched endpoints on the network
Monitoring Recommendations
- Ingest browser telemetry and OS version data into a centralized data lake for continuous version-drift monitoring
- Alert on network access from outdated Safari builds to untrusted or newly registered domains
- Track user interaction with pages that trigger high volumes of enumeration APIs such as navigator, screen, or Canvas queries
How to Mitigate CVE-2024-27838
Immediate Actions Required
- Update Safari to version 17.5 and upgrade Apple operating systems to iOS 17.5, iPadOS 17.5, iOS 16.7.8, iPadOS 16.7.8, macOS Sonoma 14.5, tvOS 17.5, visionOS 1.2, or watchOS 10.5
- Enforce update compliance through MDM policies for all managed Apple endpoints
- Restrict access to untrusted websites from devices that cannot be immediately patched
Patch Information
Apple released fixes across the affected product lines. Refer to the vendor advisories for each platform: Safari 17.5 (HT214104), iOS 17.5 and iPadOS 17.5 (HT214101), iOS 16.7.8 and iPadOS 16.7.8 (HT214100), macOS Sonoma 14.5 (HT214106), tvOS 17.5 (HT214108), visionOS 1.2 (HT214103), and watchOS 10.5 (HT214102).
Workarounds
- Use content blockers or privacy-focused Safari extensions that limit access to fingerprinting APIs
- Enable Safari's Private Browsing and Intelligent Tracking Prevention features to reduce cross-site tracking exposure
- Segment high-value users onto patched devices and block navigation to unknown domains at the network egress until updates are applied
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.