CVE-2026-78899: Google Chrome V8 Use After Free Vulnerability

CVE-2026-78899 Overview

CVE-2026-78899 is a use-after-free vulnerability in the V8 JavaScript engine of Google Chrome. The flaw affects Chrome versions prior to 152.0.7977.65 and allows a remote attacker to execute arbitrary code inside the Chrome sandbox. Exploitation requires a victim to visit a crafted HTML page. Google assigned the issue a Chromium security severity rating of High and tracks it under Chromium Issue #540430406.

Critical Impact
A remote attacker can achieve arbitrary code execution within the Chrome renderer sandbox by luring a user to a malicious web page, providing a foothold that can be chained with a sandbox escape for full compromise.

Affected Products

Google Chrome versions prior to 152.0.7977.65 (Stable channel, Desktop)
Chromium-based browsers embedding the vulnerable V8 build
Applications and frameworks bundling the affected V8 engine

Discovery Timeline

2026-08-25 - CVE-2026-78899 published to the National Vulnerability Database
2026-08-27 - NVD record last modified

Technical Details for CVE-2026-78899

Vulnerability Analysis

CVE-2026-78899 is a use-after-free condition [CWE-416] in Google's V8 JavaScript and WebAssembly engine. V8 compiles and executes JavaScript inside the Chrome renderer process. A use-after-free occurs when code continues to reference a memory object after that object has been freed. In V8, this typically arises from stale pointers in the compiler pipeline, garbage collector interactions, or object lifetime mismatches inside optimized code.

An attacker who controls the reclaimed allocation can groom the heap so that a controlled object replaces the freed structure. Subsequent access through the dangling pointer allows the attacker to read or write attacker-controlled data and hijack control flow inside the renderer process.

Successful exploitation grants code execution inside the Chrome sandbox. The sandbox constrains impact, but attackers routinely pair renderer bugs with a separate sandbox escape to obtain code execution on the host operating system.

Root Cause

The root cause is improper object lifetime management inside V8. A reference remains valid and reachable after the underlying memory has been released, violating the engine's memory safety invariants. Google has not published detailed technical analysis of the specific object or code path involved.

Attack Vector

The attack vector is network-based and requires user interaction. A target must load a crafted HTML page under attacker control, for example through a phishing link, a malicious advertisement, or a compromised third-party resource. No authentication is required. The exploit code executes as JavaScript within the victim's browser tab.

No verified proof-of-concept has been published. See Chromium Issue #540430406 for upstream tracking details.

Detection Methods for CVE-2026-78899

Indicators of Compromise

Chrome renderer processes crashing with heap corruption signatures shortly after visiting untrusted domains
Unexpected child processes spawned from chrome.exe following web browsing activity
Outbound connections from renderer processes to newly registered or low-reputation domains hosting HTML or JavaScript payloads
Browser telemetry showing users on Chrome builds older than 152.0.7977.65

Detection Strategies

Inventory installed Chrome versions across managed endpoints and flag builds below 152.0.7977.65
Monitor endpoint telemetry for anomalous behavior originating from browser renderer processes, including unusual file writes, script interpreters, or LOLBins launched by Chrome
Correlate web proxy logs with endpoint process events to identify users who loaded suspicious pages preceding renderer crashes

Monitoring Recommendations

Enable crash reporting and centralize Chrome crash telemetry to detect exploitation attempts
Alert on Chrome child processes executing shells, PowerShell, wscript, or mshta
Track egress traffic from browser processes to domains not present in enterprise allowlists

How to Mitigate CVE-2026-78899

Immediate Actions Required

Update Google Chrome to version 152.0.7977.65 or later on all Windows, macOS, and Linux endpoints
Restart Chrome after the update installs so the patched V8 binary is loaded
Verify Chromium-based browsers and embedded WebViews inherit the fixed V8 build from their vendors
Prioritize patching for users who routinely browse untrusted content or handle high-value data

Patch Information

Google addressed CVE-2026-78899 in the Chrome Stable channel release documented in the Google Chrome Stable Update advisory. The fix ships in Chrome 152.0.7977.65 for Desktop. Enterprises using managed update channels should confirm rollout completion through their deployment tooling.

Workarounds

Enforce Chrome auto-update through group policy or MDM to ensure timely patch delivery
Restrict browsing to trusted sites through web filtering while patching is in progress
Disable JavaScript on high-risk endpoints where feasible until updates are applied
Deploy site isolation and enhanced sandboxing policies to raise the cost of renderer exploitation

bash

# Verify installed Chrome version on Linux
google-chrome --version

# Verify installed Chrome version on macOS
/Applications/Google\ Chrome.app/Contents/MacOS/Google\ Chrome --version

# Verify installed Chrome version on Windows (PowerShell)
(Get-Item "C:\Program Files\Google\Chrome\Application\chrome.exe").VersionInfo.ProductVersion