CVE-2025-43443: Apple Safari DOS Vulnerability

CVE-2025-43443 Overview

CVE-2025-43443 affects 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 across its browser and operating system components. The vulnerability requires user interaction, such as visiting a malicious website, and produces an availability impact limited to process termination. It does not affect confidentiality or integrity of user data. Apple published fixes in Safari 26.1, iOS 18.7.2, iPadOS 18.7.2, iOS 26.1, iPadOS 26.1, macOS Tahoe 26.1, tvOS 26.1, visionOS 26.1, and watchOS 26.1.

Critical Impact
Remote attackers can trigger an unexpected process crash by luring a user into loading maliciously crafted web content, resulting in denial of service against the WebKit-based process.

Affected Products

Apple Safari (prior to 26.1)
Apple iOS and iPadOS (prior to 18.7.2 and 26.1)
Apple macOS Tahoe, tvOS, visionOS, and watchOS (prior to 26.1)

Discovery Timeline

2025-11-04 - CVE-2025-43443 published to the National Vulnerability Database
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-43443

Vulnerability Analysis

CVE-2025-43443 is a client-side denial-of-service issue in Apple's web content handling stack. Apple's advisory notes that processing maliciously crafted web content may lead to an unexpected process crash. The issue was addressed with improved checks, indicating that specific inputs bypassed prior validation logic during rendering or parsing operations. The vulnerability is categorized under [NVD-CWE-noinfo] because Apple did not publish a specific weakness classification. Exploitation results in loss of availability for the affected browser or WebView process, but no confidentiality or integrity impact is reported. The EPSS probability is 0.664%, reflecting a low likelihood of observed exploitation activity in the near term.

Root Cause

The root cause is insufficient validation of untrusted web content processed by Safari and the shared WebKit components used across Apple operating systems. Apple's remediation note — "addressed with improved checks" — indicates the fix introduces additional input or state validation to reject malformed content that previously reached vulnerable code paths and triggered a crash.

Attack Vector

An attacker hosts crafted web content on a controlled site or delivers it through an embedded WebView, advertisement, or link. When a user visits the site or loads the content, the affected process parses the input and terminates unexpectedly. The attack requires network reachability and user interaction, but no authentication or elevated privileges. Because WebKit is used system-wide on Apple platforms, applications that embed web views inherit the same exposure until patched.

No public exploit code, proof-of-concept, or CISA KEV listing is associated with this CVE at the time of publication. Refer to Apple's advisories for technical scope: Apple Support Document #125632, Apple Support Document #125633, Apple Support Document #125634, Apple Support Document #125637, Apple Support Document #125638, Apple Support Document #125639, and Apple Support Document #125640.

Detection Methods for CVE-2025-43443

Indicators of Compromise

Repeated unexpected termination of Safari or WebKit-based processes (com.apple.WebKit.WebContent) shortly after loading specific URLs.
Crash reports referencing WebKit or web content processes generated on macOS, iOS, iPadOS, tvOS, visionOS, or watchOS devices.
Browser tabs consistently crashing on the same third-party or advertising domain.

Detection Strategies

Collect and review crash logs from managed Apple endpoints for anomalous WebKit process terminations tied to specific sites.
Correlate proxy or DNS logs with reported crash events to identify potentially malicious content delivery domains.
Track Safari and OS build versions across the fleet to identify hosts still exposed to CVE-2025-43443.

Monitoring Recommendations

Enable centralized collection of macOS DiagnosticReports and iOS crash telemetry through your MDM or endpoint telemetry pipeline.
Alert on clusters of WebKit crashes originating from a common referrer or URL pattern.
Monitor patch compliance for Safari 26.1 and the corresponding OS releases across managed devices.

How to Mitigate CVE-2025-43443

Immediate Actions Required

Update Safari to version 26.1 on all supported macOS systems.
Update Apple devices to iOS 18.7.2, iPadOS 18.7.2, iOS 26.1, iPadOS 26.1, macOS Tahoe 26.1, tvOS 26.1, visionOS 26.1, or watchOS 26.1 as applicable.
Push updates through MDM policies and enforce compliance deadlines for user-owned devices under BYOD programs.

Patch Information

Apple resolved the vulnerability with improved checks in Safari 26.1 and in the 26.1 releases of iOS, iPadOS, macOS Tahoe, tvOS, visionOS, and watchOS, and in iOS 18.7.2 and iPadOS 18.7.2 for legacy device support. See the linked Apple Support documents for release-specific details and build numbers.

Workarounds

Restrict browsing to trusted sites and enable content-filtering solutions to block known-malicious domains until patches are applied.
Disable JavaScript for untrusted sites in Safari settings where operationally feasible to reduce the WebKit attack surface.
Consider using an alternate, patched browser for high-risk browsing tasks on devices that cannot be updated immediately.

bash

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

# Check macOS build
sw_vers

# Trigger managed software update via MDM CLI (example: Jamf)
sudo jamf policy -event install-apple-updates