CVE-2020-16009

What is Chromium's V8 Engine?

V8 is the JavaScript and WebAssembly engine at the core of Google Chrome and every other Chromium-based browser, compiling and executing the JavaScript on every web page a user visits. Because V8 runs untrusted, attacker-supplied JavaScript by design, bugs in its type system are a direct and reliable path to remote code execution in the browser renderer.

Overview

CVE-2020-16009 is a type confusion vulnerability (CWE-787) in V8 that allows heap corruption exploitation via a crafted HTML page (CVSS 3.1: AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H, 8.8 High). It was patched in the same November 2020 timeframe as the closely related CVE-2020-16013 (also enriched on this site) — part of a documented cluster of Chromium V8 vulnerabilities that Google fixed in quick succession as active exploitation was confirmed in the wild.

Technical Details

Type confusion occurs when V8's internal engine logic treats a value as one JavaScript type when it's actually a different, incompatible type at the machine level — carefully crafted JavaScript can set up this mismatch and then exploit the resulting memory corruption for arbitrary code execution within the renderer process. Because the bug lives in V8 itself, it affects every Chromium-based browser (Chrome, Edge, Opera, and others), not just Google's own product.

Discovery

Identified through Google's internal security research process during the same period that produced CVE-2020-16013 and other related V8 fixes.

Exploitation Context

This CVE is part of the same late-2020 wave of actively-exploited Chromium 0-days documented under CVE-2020-16013, which also covers this period's pairing with the Windows kernel privilege-escalation bug CVE-2020-17087 for full sandbox-escape exploitation chains.

Remediation

1. Update Chrome and any other Chromium-based browser to the version including the November 2020 fix or later.
2. Patch the underlying OS alongside the browser — see CVE-2020-17087 for the Windows kernel half of this period's documented exploitation chains.
3. Enable and verify Site Isolation in your browser deployment as defense-in-depth against renderer-level compromise.
4. Treat systems running an unpatched Chromium-based browser through November 2020 as potential compromise candidates given the confirmed active-exploitation status of this vulnerability cluster.