CVE-2025-31217 Overview
CVE-2025-31217 is an improper input validation vulnerability [CWE-20] affecting Apple Safari and multiple Apple operating systems. Processing maliciously crafted web content can trigger an unexpected Safari crash, resulting in denial of service. The flaw stems from insufficient validation of untrusted input during web content processing. Apple addressed the issue with improved input validation in Safari 18.5, iOS 18.5, iPadOS 18.5, iPadOS 17.7.7, macOS Sequoia 15.5, tvOS 18.5, visionOS 2.5, and watchOS 11.5. The vulnerability requires user interaction because a victim must visit a malicious page or open crafted web content.
Critical Impact
A remote attacker hosting malicious web content can crash Safari on unpatched Apple devices, disrupting availability across iOS, iPadOS, macOS, tvOS, visionOS, and watchOS.
Affected Products
- Apple Safari versions before 18.5
- Apple iOS before 18.5, iPadOS before 18.5, and iPadOS 17.x before 17.7.7
- Apple macOS Sequoia before 15.5, tvOS before 18.5, visionOS before 2.5, and watchOS before 11.5
Discovery Timeline
- 2025-05-12 - CVE-2025-31217 published to the National Vulnerability Database (NVD)
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-31217
Vulnerability Analysis
CVE-2025-31217 is a client-side input validation defect in Safari's web content processing pipeline. The browser fails to properly validate the structure or values of certain fields within maliciously crafted web content. When Safari parses this content, the unchecked input drives the process into an unexpected state and terminates the browser. The result is an availability impact limited to the Safari process context, without direct confidentiality or integrity loss. The issue is reachable from any web page an attacker can convince a user to load, giving it a network-based attack surface.
Root Cause
According to Apple's advisory, the underlying defect is insufficient input validation in the code that handles web content. The vendor resolved the issue by hardening input validation logic. The Common Weakness Enumeration classification [CWE-20] confirms that the primary failure is improper input validation rather than a memory-safety flaw with code execution potential.
Attack Vector
Exploitation requires a user to visit a malicious website or otherwise render attacker-controlled web content in Safari or WebKit-based views on the affected operating systems. No authentication is required. Because user interaction is necessary, phishing links, malicious advertisements, and compromised third-party sites are the most likely delivery channels. Successful exploitation crashes Safari; no privilege escalation or data exfiltration is described in the advisory.
No public proof-of-concept code has been released. See the Apple security advisories and the associated Full Disclosure discussion threads for additional technical context.
Detection Methods for CVE-2025-31217
Indicators of Compromise
- Repeated unexpected Safari process terminations or com.apple.WebKit.WebContent crash reports following navigation to untrusted URLs.
- Crash logs under ~/Library/Logs/DiagnosticReports/ referencing Safari or WebKit shortly after visiting a suspicious page.
- Outbound network connections to newly registered or low-reputation domains immediately preceding browser crashes.
Detection Strategies
- Monitor endpoint telemetry for abnormal Safari or WebKit crash frequency on macOS, iOS, iPadOS, and related Apple platforms.
- Correlate browser crash events with recent URL navigation history to identify candidate malicious pages.
- Track Apple OS and Safari version inventory to identify endpoints running versions earlier than the fixed builds.
Monitoring Recommendations
- Ingest macOS unified logs and diagnostic crash reports into a centralized log platform for cross-endpoint analysis.
- Alert on clusters of Safari crashes tied to a shared referrer domain, which may indicate active exploitation attempts.
- Enrich web proxy logs with threat intelligence to flag connections to domains hosting known malicious web content.
How to Mitigate CVE-2025-31217
Immediate Actions Required
- Update Safari to version 18.5 and upgrade Apple operating systems to iOS 18.5, iPadOS 18.5, iPadOS 17.7.7, macOS Sequoia 15.5, tvOS 18.5, visionOS 2.5, or watchOS 11.5.
- Prioritize patching of user-facing endpoints that regularly browse untrusted web content.
- Advise users to avoid clicking untrusted links until affected devices are updated.
Patch Information
Apple released fixes across its product line with improved input validation. Refer to the vendor advisories for build-specific details: Apple Support Article 122404, Apple Support Article 122405, Apple Support Article 122716, Apple Support Article 122719, Apple Support Article 122720, Apple Support Article 122721, and Apple Support Article 122722.
Workarounds
- Restrict browsing to trusted sites and enable content filtering at the network perimeter until patches are deployed.
- Deploy mobile device management (MDM) policies that enforce minimum Apple OS versions across managed fleets.
- Consider using an alternate updated browser on macOS for high-risk browsing sessions while Safari updates propagate.
# Verify installed Safari and macOS versions on managed endpoints
sw_vers -productVersion
defaults read /Applications/Safari.app/Contents/Info.plist CFBundleShortVersionString
# Example MDM compliance check (pseudo-configuration)
# require: macOS >= 15.5, Safari >= 18.5
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
