CVE-2025-43430 Overview
CVE-2025-43430 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 in the browser rendering engine. Apple addressed the issue through improved state management in Safari 26.1 and companion OS updates.
The flaw requires user interaction, such as visiting an attacker-controlled webpage, and does not impact confidentiality or integrity. Its impact is limited to availability through a denial-of-service condition on the affected process.
Critical Impact
Attackers hosting malicious web content can crash the Safari rendering process on unpatched Apple devices, disrupting browsing sessions across iOS, iPadOS, macOS, tvOS, visionOS, and watchOS.
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-2025-43430 published to the National Vulnerability Database
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-43430
Vulnerability Analysis
CVE-2025-43430 is classified as an improper input validation issue [CWE-20] in Apple's web content processing stack. When Safari or a WebKit-based component parses maliciously crafted web content, internal state transitions are not handled correctly. The result is an unexpected process crash within the affected rendering component.
According to Apple, the fix was implemented through improved state management, indicating the root cause involved inconsistent or unchecked object state during content processing. The vulnerability is exploitable remotely across the network but requires the victim to load attacker-controlled content, such as by visiting a webpage.
The crash results in a denial-of-service condition against the browser process. Apple has not disclosed evidence of remote code execution potential in the advisories, and the confidentiality and integrity impact fields are marked as none.
Root Cause
The root cause is improper handling of state within Apple's web content parsing logic. Specially crafted markup or scripting content drives the affected component into an unexpected state, leading to a process termination. Apple's remediation strengthens state validation to reject or safely handle these transitions.
Attack Vector
Exploitation occurs over the network with low attack complexity. An attacker hosts crafted content on a webpage, delivers it via an embedded frame, or sends it through any channel that renders web content in Safari or WebKit. When the victim opens the content, the process crashes. No privileges are required, but user interaction is necessary.
Refer to the Apple Security Advisory #125634 for technical details on the fixed component.
Detection Methods for CVE-2025-43430
Indicators of Compromise
- Repeated unexpected termination of Safari or WebContent processes shortly after loading specific URLs.
- Crash reports referencing WebKit rendering components generated on iOS, iPadOS, macOS, tvOS, visionOS, or watchOS devices.
- Outbound connections from managed devices to URLs known to serve malformed HTML, CSS, or JavaScript payloads.
Detection Strategies
- Monitor endpoint telemetry for abnormal Safari or WebKit process exit codes and crash frequency spikes.
- Correlate browser crashes with recent navigation events to identify suspicious triggering URLs.
- Track Apple OS build versions across the fleet to identify hosts still running vulnerable releases prior to 26.1.
Monitoring Recommendations
- Ingest macOS ReportCrash and iOS diagnostic logs into a centralized logging platform for correlation.
- Alert on repeated WebContent process terminations from the same origin domain within short intervals.
- Track proxy and DNS logs for user visits to newly registered or low-reputation domains preceding browser crashes.
How to Mitigate CVE-2025-43430
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 users who regularly browse untrusted external content or handle sensitive workflows in Safari.
- Enforce update compliance through mobile device management (MDM) policies across managed Apple endpoints.
Patch Information
Apple released fixes in Safari 26.1 and the 26.1 updates for iOS, iPadOS, macOS Tahoe, tvOS, visionOS, and watchOS. See the vendor advisories: Apple Security Advisory #125632, #125637, #125638, #125639, and #125640.
Workarounds
- Restrict browsing to trusted sites until patches are deployed on all Apple endpoints.
- Use content filtering or secure web gateways to block access to known malicious or low-reputation domains.
- Disable JavaScript in Safari for high-risk user groups where compatible with business workflows.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
