CVE-2025-43425: Apple Safari DoS Vulnerability

CVE-2025-43425 Overview

CVE-2025-43425 is a memory handling vulnerability affecting Apple's WebKit-based products across Safari, iOS, iPadOS, macOS, tvOS, visionOS, and watchOS. Processing maliciously crafted web content can trigger an unexpected process crash on affected devices. Apple addressed the issue through improved memory handling in the 26.1 release wave.

The flaw is categorized under [CWE-119] (improper restriction of operations within the bounds of a memory buffer) and requires user interaction, such as visiting an attacker-controlled webpage. No authentication is required, and the attack originates over the network.

Critical Impact
Successful exploitation results in denial of service through an unexpected process termination when a victim loads malicious web content in a vulnerable Apple browser or embedded WebKit view.

Affected Products

Apple Safari (prior to 26.1)
Apple iOS and iPadOS (prior to 26.1)
Apple macOS Tahoe (prior to 26.1), tvOS, visionOS, and watchOS (prior to 26.1)

Discovery Timeline

2025-11-04 - CVE-2025-43425 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-43425

Vulnerability Analysis

The vulnerability resides in WebKit, the browser engine that powers Safari and all web content rendering across Apple's operating systems. Improper memory handling during the processing of crafted web content leads to an unexpected process crash. The condition falls under [CWE-119], where operations exceed the intended bounds of a memory buffer.

The impact is limited to availability. Confidentiality and integrity are not affected according to the CVSS vector, and the flaw does not enable code execution or memory disclosure based on Apple's advisory language. Exploitation requires a user to visit or otherwise process attacker-controlled web content.

An EPSS probability of 0.65% (46.87 percentile) suggests limited near-term exploitation activity. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog, and no public proof-of-concept has been published at the time of this writing.

Root Cause

Apple attributes the issue to memory handling that did not correctly bound operations while parsing or rendering specific web content structures. The fix improves memory handling to prevent the out-of-bounds condition that triggered the crash. Apple has not published low-level technical details beyond the advisory description.

Attack Vector

An attacker hosts crafted HTML, JavaScript, or related web resources on a malicious site or delivers them through iframes, ads, or embedded web views within third-party apps. When a user opens the content in a vulnerable version of Safari or another WebKit-based client, the rendering process crashes.

Because WebKit is used across iOS, iPadOS, macOS, tvOS, visionOS, and watchOS, any application embedding a WKWebView or SFSafariViewController on an unpatched device is potentially exposed.

Detection Methods for CVE-2025-43425

Indicators of Compromise

Repeated crashes of Safari, com.apple.WebKit.WebContent, or WebKit-hosting applications on unpatched devices
Crash reports referencing WebKit frames after visiting untrusted URLs
Outbound connections from managed devices to newly registered or low-reputation domains preceding browser crashes

Detection Strategies

Collect and centralize Apple device crash logs and correlate WebKit process terminations with recently visited URLs
Monitor mobile device management (MDM) telemetry for devices running WebKit builds prior to the 26.1 update wave
Use web proxy and DNS logs to identify user navigation to suspicious domains preceding crash events

Monitoring Recommendations

Track Apple software version inventory across managed endpoints to identify systems missing the 26.1 patch set
Alert on abnormal frequency of WebKit process restarts on individual endpoints
Review browser and web view crash telemetry from any in-house iOS or macOS applications embedding WebKit

How to Mitigate CVE-2025-43425

Immediate Actions Required

Update all Apple devices to Safari 26.1, iOS 26.1, iPadOS 26.1, macOS Tahoe 26.1, tvOS 26.1, visionOS 26.1, and watchOS 26.1
Prioritize patching for devices used to browse untrusted or user-selected web content
Verify that MDM policies enforce the updated OS versions across the fleet

Patch Information

Apple released fixes in the 26.1 update train. Refer to the vendor advisories for platform-specific details: Apple Support Document #125632, Apple Support Document #125634, Apple Support Document #125637, Apple Support Document #125638, Apple Support Document #125639, and Apple Support Document #125640.

Workarounds

Restrict browsing to trusted sites until the 26.1 update can be deployed
Use content filtering and DNS-layer blocking to reduce exposure to untrusted web content
Disable or restrict third-party applications that embed WebKit views if timely patching is not feasible

bash

# Verify installed macOS version meets the patched build
sw_vers -productVersion

# Verify installed Safari version on macOS
mdls -name kMDItemVersion /Applications/Safari.app