CVE-2025-43440 Overview
CVE-2025-43440 is a vulnerability affecting Apple Safari and multiple Apple operating systems. Processing maliciously crafted web content may lead to an unexpected process crash. Apple addressed the issue with improved checks in Safari 26.1, iOS 26.1, iPadOS 26.1, macOS Tahoe 26.1, tvOS 26.1, visionOS 26.1, and watchOS 26.1.
The flaw is categorized under [CWE-79] and is exploitable over the network with user interaction required. The impact is limited to availability, resulting in a denial-of-service condition against the affected process rather than code execution or data disclosure.
Critical Impact
Remote attackers can trigger an unexpected process crash by luring a user to view maliciously crafted web content, disrupting browser and WebKit-based application availability across Apple platforms.
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-2025-43440 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-43440
Vulnerability Analysis
The vulnerability resides in the handling of web content within Apple's WebKit-based rendering stack, which is shared across Safari, iOS, iPadOS, macOS, tvOS, visionOS, and watchOS. When the affected components process specific malformed inputs delivered through a web page, insufficient validation causes the rendering process to enter an unexpected state and terminate. Apple's advisory states the issue was resolved with improved checks in version 26.1 across the affected platforms.
Exploitation requires a user to visit or interact with attacker-controlled content. Successful triggering does not yield code execution or information disclosure based on the vendor description, but availability of the affected process is impacted.
Root Cause
The root cause is missing or insufficient input validation while parsing untrusted web content. Apple's fix note — "addressed with improved checks" — indicates that additional boundary or state validation was introduced to prevent the malformed input from reaching the unsafe code path. The advisory does not disclose the specific component or object type responsible for the crash.
Attack Vector
An attacker hosts crafted content on a web page or delivers it through an embedded WebView. When a user loads the page in Safari or another WebKit consumer on an unpatched Apple platform, the malformed content triggers the fault and causes the process to crash. No authentication is required, and the attack is delivered entirely over the network.
Because no verified proof-of-concept has been published and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog, real-world exploitation activity has not been reported. Refer to the Apple Security Advisory #125634 for vendor technical details.
Detection Methods for CVE-2025-43440
Indicators of Compromise
- Repeated Safari or WebKit process crashes correlating with browsing activity to untrusted domains.
- Crash reports referencing WebKit rendering components on devices running versions earlier than 26.1.
- Outbound requests to newly registered or low-reputation domains preceding browser process termination.
Detection Strategies
- Collect and centralize macOS and iOS crash logs, and alert on clusters of WebKit process terminations across multiple endpoints.
- Correlate browser crash timestamps with proxy or DNS logs to identify shared malicious URLs.
- Monitor for phishing campaigns and social engineering lures directing users to attacker-controlled web content.
Monitoring Recommendations
- Track Safari and WebKit version inventory across managed macOS and iOS fleets to identify unpatched devices.
- Alert on browser crash frequency exceeding an established baseline on individual endpoints.
- Ingest MDM telemetry to confirm timely rollout of Apple 26.1 updates.
How to Mitigate CVE-2025-43440
Immediate Actions Required
- Update Safari to 26.1 and upgrade iOS, iPadOS, macOS Tahoe, tvOS, visionOS, and watchOS to their 26.1 releases.
- Prioritize patching on devices used by high-risk users such as executives, developers, and IT administrators.
- Enforce automatic updates through MDM policies to ensure sustained coverage.
Patch Information
Apple resolved the issue in Safari 26.1, iOS 26.1, iPadOS 26.1, macOS Tahoe 26.1, tvOS 26.1, visionOS 26.1, and watchOS 26.1. Full details are available in the Apple Security Advisory #125632, Advisory #125637, Advisory #125638, Advisory #125639, and Advisory #125640.
Workarounds
- Restrict browsing to trusted domains using web filtering or DNS-based reputation controls until patches are applied.
- Disable JavaScript in Safari for high-risk browsing sessions where feasible.
- Educate users to avoid clicking links from unsolicited messages while unpatched devices remain in the environment.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
