CVE-2026-43715: Apple Safari Use-After-Free Vulnerability

CVE-2026-43715 Overview

CVE-2026-43715 is a use-after-free vulnerability [CWE-416] affecting Apple Safari, iOS, iPadOS, and macOS. Processing maliciously crafted web content triggers memory corruption in the browser engine. Apple addressed the issue with improved memory management in Safari 26.5.2, iOS 26.5.2, iPadOS 26.5.2, and macOS Tahoe 26.5.2.

The vulnerability requires user interaction, such as visiting an attacker-controlled webpage. Successful exploitation can lead to arbitrary code execution within the browser process. No public proof-of-concept exists at the time of publication, and CISA has not added this CVE to its Known Exploited Vulnerabilities catalog.

Critical Impact
Attackers hosting malicious web content can trigger memory corruption on unpatched Apple devices, potentially leading to arbitrary code execution with the same privileges as the browser process.

Affected Products

Apple Safari (versions prior to 26.5.2)
Apple iOS and iPadOS (versions prior to 26.5.2)
Apple macOS Tahoe (versions prior to 26.5.2)

Discovery Timeline

2026-06-29 - CVE-2026-43715 published to the National Vulnerability Database
2026-06-30 - CVE-2026-43715 last updated in NVD database

Technical Details for CVE-2026-43715

Vulnerability Analysis

CVE-2026-43715 is a use-after-free condition triggered by processing maliciously crafted web content. In a use-after-free flaw, code continues to reference a memory region after it has been freed, allowing attackers to manipulate the freed allocation to control program execution.

Apple's advisory states the issue was addressed with improved memory management. This language typically indicates changes to object lifetime handling, reference counting, or allocator behavior within Safari's rendering pipeline. The vulnerability affects the shared WebKit engine used across Safari, iOS, iPadOS, and macOS.

Root Cause

The root cause is dangling pointer access within Safari's web content processing components. An object is freed while another code path retains a reference to it. Subsequent operations on that stale reference read or write freed memory, corrupting heap structures.

Attack Vector

Exploitation requires a victim to load attacker-controlled web content in Safari or an application that embeds WebKit. The attack occurs over the network with low complexity and does not require authentication. Adversaries can deliver payloads through drive-by downloads, malicious advertisements, phishing links, or compromised legitimate sites.

The vulnerability aligns with common WebKit exploitation patterns, where attackers spray the heap, free a targeted object, and reclaim the slot with attacker-controlled data. Refer to the Apple Security Advisory 127594 for vendor-provided technical context.

Detection Methods for CVE-2026-43715

Indicators of Compromise

Safari or WebKit-based application crashes with signatures pointing to heap corruption or freed-object access during web browsing sessions.
Unexpected child processes spawned by Safari, com.apple.WebKit.WebContent, or applications embedding WKWebView.
Outbound network connections from browser processes to newly registered or low-reputation domains immediately after page loads.

Detection Strategies

Monitor endpoint telemetry for anomalous WebKit process behavior, including memory access violations and unexpected code execution paths.
Correlate browser crash reports (~/Library/Logs/DiagnosticReports/) with URLs visited near the time of the crash.
Deploy web filtering to identify and block known malicious domains delivering browser exploit payloads.

Monitoring Recommendations

Track Safari and WebKit version strings across the fleet to identify hosts still running vulnerable builds prior to 26.5.2.
Alert on process injection attempts or unexpected dynamic library loads targeting Safari or WebKit host processes.
Review DNS and proxy logs for traffic to domains associated with browser exploitation kits.

How to Mitigate CVE-2026-43715

Immediate Actions Required

Update Safari, iOS, iPadOS, and macOS to version 26.5.2 or later across all managed Apple devices.
Prioritize patching for high-risk users, including executives, developers, and personnel with access to sensitive data.
Enforce automatic updates through MDM policies to reduce exposure windows on user-managed devices.

Patch Information

Apple released fixes in Safari 26.5.2, iOS 26.5.2, iPadOS 26.5.2, and macOS Tahoe 26.5.2. Detailed advisories are available at Apple Security Advisory 127594, Apple Security Advisory 127595, and Apple Security Advisory 127685.

Workarounds

Restrict browsing to trusted sites through enterprise web gateways until patches are deployed.
Enable Lockdown Mode on iOS, iPadOS, and macOS for high-risk users to reduce the WebKit attack surface.
Block execution of untrusted WebKit-embedding applications through application allowlisting where feasible.

bash

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

# Check macOS build version
sw_vers

# Trigger software update check
sudo softwareupdate -l
sudo softwareupdate -ia --restart