CVE-2025-31215: Apple Safari DOS Vulnerability

CVE-2025-31215 Overview

CVE-2025-31215 is an input validation vulnerability [CWE-20] affecting Apple Safari and multiple Apple operating systems. Processing maliciously crafted web content can trigger an unexpected process crash. Apple addressed the issue with improved checks across its product line.

The vulnerability impacts WebKit-based content rendering and requires user interaction, such as visiting a malicious webpage. While the flaw does not expose confidentiality or integrity, it allows attackers to disrupt browser availability remotely.

Critical Impact

Remote attackers can crash Safari and related WebKit processes on iOS, iPadOS, macOS, tvOS, visionOS, and watchOS by serving malicious web content to a victim.

Affected Products

• Apple Safari (prior to 18.5)
• Apple iOS and iPadOS (prior to 18.5, iPadOS 17.7.7)
• Apple macOS Sequoia (prior to 15.5), tvOS (prior to 18.5), visionOS (prior to 2.5), watchOS (prior to 11.5)

Discovery Timeline

• 2025-05-12 - CVE-2025-31215 published to NVD
• 2026-04-02 - Last updated in NVD database

Technical Details for CVE-2025-31215

Vulnerability Analysis

The vulnerability stems from improper input validation [CWE-20] when Apple's WebKit engine processes specially crafted web content. Insufficient checks on untrusted input cause the rendering process to enter an unexpected state and terminate abnormally.

The flaw is network-exploitable and requires user interaction, typically by visiting an attacker-controlled webpage. Exploitation results in availability loss for the affected process, with no direct impact to confidentiality or integrity. The EPSS score of 1.121% places it in the 78th percentile, indicating moderate likelihood of exploitation activity.

Root Cause

Apple's advisory describes the issue as one of missing validation checks in WebKit content parsing. Without sufficient sanity checks, malformed web content drives the parser or renderer into an invalid condition, causing the process to crash. Apple addressed the root cause by adding improved input checks throughout the affected code paths.

Attack Vector

An attacker hosts malicious HTML, JavaScript, or other web content on a controlled site or injects it into a compromised site. When a victim using a vulnerable Apple device loads the content in Safari or any WebKit-backed view, the rendering process terminates. Repeated triggering can prevent normal browser usage and may serve as a building block in chained exploitation against WebKit.

No verified public proof-of-concept code is associated with this CVE. Technical details are described in the referenced Apple Support advisories and Full Disclosure mailing list posts.

Detection Methods for CVE-2025-31215

Indicators of Compromise

• Recurring crash reports for com.apple.WebKit.WebContent or Safari renderer processes across managed Apple endpoints
• macOS crash logs in ~/Library/Logs/DiagnosticReports/ referencing WebKit content process termination
• Outbound connections from Safari to recently registered or low-reputation domains immediately preceding crashes

Detection Strategies

• Correlate process termination events for Safari and WebKit content processes with preceding network activity to identify suspicious browsing patterns
• Monitor MDM-reported application crash telemetry on iOS, iPadOS, and macOS fleets for spikes against single domains
• Track Safari and WebKit version reporting to identify endpoints running pre-18.5 builds vulnerable to CVE-2025-31215

Monitoring Recommendations

• Aggregate browser crash telemetry into a centralized data lake or SIEM for cross-fleet correlation
• Enrich web proxy and DNS logs with reputation data to surface malicious sites delivering exploit content
• Alert on patterns where multiple users visit the same URL followed by WebKit process crashes

How to Mitigate CVE-2025-31215

Immediate Actions Required

• Update all Apple devices to Safari 18.5, iOS 18.5, iPadOS 18.5, iPadOS 17.7.7, macOS Sequoia 15.5, tvOS 18.5, visionOS 2.5, or watchOS 11.5
• Inventory Apple endpoints using MDM to identify unpatched systems and enforce update compliance
• Restrict browsing on unpatched devices to trusted destinations until updates are deployed

Patch Information

Apple released fixes in Safari 18.5, iOS 18.5 and iPadOS 18.5, iPadOS 17.7.7, macOS Sequoia 15.5, tvOS 18.5, visionOS 2.5, and watchOS 11.5. Reference details are available in Apple Support Document #122404, #122405, #122716, #122719, #122720, #122721, and #122722. Debian users of WebKitGTK should consult the Debian LTS advisory.

Workarounds

• Block known malicious domains at the network perimeter and via DNS filtering until patches are applied
• Disable JavaScript for untrusted sites in Safari settings to reduce attack surface on unpatched devices
• Use enterprise content filtering to enforce safe browsing policies on managed Apple endpoints