CVE-2019-8506

What Is Affected?

This vulnerability affects WebKit, the browser engine shared across Safari and other Apple products (iOS, macOS, tvOS, watchOS), which renders all web content a user views — making it one of the most commonly targeted attack surfaces for browser-based exploit chains.

Overview

CVE-2019-8506 is a type confusion vulnerability (CWE-843) that can be triggered by processing maliciously crafted web content, allowing an attacker to execute arbitrary code. It carries a high severity rating (CVSS 8.8) and requires a user to visit a malicious or compromised web page (or open malicious content), after which no further interaction is needed for exploitation to proceed.

Technical Details

A type confusion bug occurs when code treats a memory object as one type while it is actually another, letting an attacker manipulate memory in ways the program logic did not anticipate — typically abused to corrupt memory and redirect program execution toward attacker-controlled code, often as the initial step in a larger exploit chain pairing a memory-corruption bug with a separate sandbox-escape or privilege-escalation flaw.

Discovery

Fixed by Apple as part of its December 2019 security updates across iOS, macOS, tvOS, and watchOS; NVD does not credit an individual external researcher for this entry.

Exploitation Context

CISA added this CVE to the KEV catalog in May 2022, indicating confirmed real-world exploitation. WebKit memory-corruption bugs of this kind are a recurring building block in both cybercriminal drive-by-download campaigns and more sophisticated targeted spyware exploit chains, which routinely combine a WebKit code-execution bug with a separate kernel or sandbox-escape flaw for full device compromise.

Remediation

1. Update all affected Apple devices to the latest supported iOS, iPadOS, macOS, tvOS, and watchOS versions.
2. Enable automatic updates so future WebKit security fixes are applied promptly.
3. High-risk users should consider enabling Apple's Lockdown Mode.
4. Avoid clicking links or opening web content from untrusted or unsolicited sources.
5. Maintain endpoint monitoring capable of detecting exploitation attempts against browser engines where available.