CVE-2026-64783: Apple Safari Use-After-Free Vulnerability

CVE-2026-64783 Overview

CVE-2026-64783 is a use-after-free vulnerability affecting Apple Safari and multiple Apple operating systems. The flaw exists in the web content processing engine and can be triggered when a user visits a maliciously crafted webpage. Successful exploitation leads to memory corruption and an unexpected Safari crash, with potential for arbitrary code execution in the browser process. Apple addressed the issue with improved memory management across Safari 26.6, iOS 26.6, iPadOS 26.6, macOS Tahoe 26.6, visionOS 26.6, and watchOS 26.6. The vulnerability is classified under CWE-416: Use After Free.

Critical Impact
Processing maliciously crafted web content may lead to an unexpected Safari crash and potential memory corruption exploitation.

Affected Products

Apple Safari (versions prior to 26.6)
Apple iOS and iPadOS (versions prior to 26.6)
Apple macOS Tahoe (versions prior to 26.6)
Apple visionOS and watchOS (versions prior to 26.6)

Discovery Timeline

2026-07-27 - CVE-2026-64783 published to NVD
2026-07-28 - Last updated in NVD database

Technical Details for CVE-2026-64783

Vulnerability Analysis

CVE-2026-64783 is a use-after-free flaw in the web content processing path used by Safari and Apple's WebKit-based rendering across iOS, iPadOS, macOS, visionOS, and watchOS. Use-after-free conditions occur when code references memory after it has been freed, allowing attackers to influence what data occupies the freed region. In browser engines, these primitives are commonly chained with heap grooming to gain arbitrary read/write and eventually code execution within the renderer sandbox. The vulnerability requires user interaction, typically visiting a malicious page or opening attacker-controlled content in the browser.

Root Cause

The root cause is improper object lifetime management in the web content handler. A freed object continues to be referenced by another code path, and the stale pointer is dereferenced during subsequent operations on the page. Apple's fix introduces improved memory management to ensure references are invalidated when the underlying object is destroyed.

Attack Vector

Exploitation is network-based and requires user interaction. An attacker hosts crafted HTML, JavaScript, or media content on a webpage and induces a target to load it in Safari or another WebKit-backed context. The malicious content triggers the freed-object reference during rendering or script execution. See the Apple security advisories for affected component context; no public exploit or proof-of-concept has been released.

Detection Methods for CVE-2026-64783

Indicators of Compromise

Repeated unexpected crashes of Safari or the com.apple.WebKit.WebContent process on endpoints running versions prior to 26.6.
Crash reports referencing WebKit rendering components with signatures consistent with use-after-free memory corruption.
Outbound connections from Safari to newly registered or low-reputation domains immediately preceding a renderer crash.

Detection Strategies

Inventory Apple endpoints and identify systems running Safari, iOS, iPadOS, macOS, visionOS, or watchOS versions below 26.6.
Correlate browser crash telemetry with recent web browsing history to identify potentially malicious pages.
Monitor endpoint logs for WebKit process termination events followed by anomalous child process activity.

Monitoring Recommendations

Ingest macOS and iOS crash reports into a centralized logging platform to establish a baseline and flag deviations.
Alert on Safari or WebKit renderer crashes that coincide with visits to uncategorized or newly seen domains.
Track patch compliance status for Safari 26.6 and the corresponding OS updates across the managed fleet.

How to Mitigate CVE-2026-64783

Immediate Actions Required

Update Safari to version 26.6 and upgrade affected Apple operating systems to iOS 26.6, iPadOS 26.6, macOS Tahoe 26.6, visionOS 26.6, and watchOS 26.6.
Enforce patch deployment through MDM policies for managed Apple devices.
Instruct users to avoid clicking untrusted links and to close Safari immediately if unexpected crashes occur.

Patch Information

Apple released fixes in Safari 26.6 and the corresponding platform updates. Refer to the vendor advisories: Apple Support #128066, Apple Support #128067, Apple Support #128068, Apple Support #128070, and Apple Support #128073.

Workarounds

Restrict Safari usage on unpatched devices and route web traffic through an alternative, patched browser where feasible.
Enable Lockdown Mode on high-risk iOS, iPadOS, and macOS devices to reduce the WebKit attack surface.
Deploy web filtering to block access to known malicious and uncategorized domains until patching completes.

bash

# Verify Safari version on macOS
defaults read /Applications/Safari.app/Contents/Info.plist CFBundleShortVersionString

# Trigger a software update check via MDM or locally
sudo softwareupdate --install --all --restart