CVE-2026-5869: Google Chrome WebML Buffer Overflow Flaw

CVE-2026-5869 Overview

A heap buffer overflow vulnerability has been identified in the WebML component of Google Chrome prior to version 147.0.7727.55. This memory corruption flaw allows a remote attacker to obtain potentially sensitive information from process memory by enticing a victim to visit a crafted HTML page. The vulnerability is classified as CWE-122 (Heap-based Buffer Overflow) and has been rated as High severity by the Chromium security team.

Critical Impact

Remote attackers can exploit this heap buffer overflow to read sensitive data from Chrome's process memory, potentially exposing credentials, session tokens, or other confidential information through malicious web content.

Affected Products

• Google Chrome versions prior to 147.0.7727.55
• Chromium-based browsers using vulnerable WebML implementation
• Desktop platforms running affected Chrome versions

Discovery Timeline

• 2026-04-08 - CVE-2026-5869 published to NVD
• 2026-04-08 - Last updated in NVD database

Technical Details for CVE-2026-5869

Vulnerability Analysis

This vulnerability resides in the WebML component of Google Chrome, which handles machine learning operations within the browser. The heap buffer overflow occurs when WebML processes specially crafted input, causing the browser to read beyond the allocated memory boundaries. This out-of-bounds read condition can expose sensitive data residing in adjacent heap memory regions.

The vulnerability is particularly concerning because it can be triggered remotely through malicious web content. An attacker can craft a specially designed HTML page that, when visited by a victim, triggers the vulnerable code path in the WebML implementation. The resulting information disclosure could expose authentication tokens, cryptographic keys, or other sensitive data present in the browser's memory space.

Root Cause

The root cause is a heap-based buffer overflow (CWE-122) in Chrome's WebML implementation. The vulnerable code fails to properly validate buffer boundaries when processing certain machine learning operations, allowing read operations to extend beyond the allocated memory region. This insufficient bounds checking enables attackers to access memory contents that should be inaccessible.

Attack Vector

The attack can be executed remotely by convincing a user to navigate to a malicious webpage. The attacker embeds specially crafted WebML operations within an HTML page that trigger the vulnerable code path. When the victim's browser renders the page and processes the malicious WebML content, the heap buffer overflow occurs, potentially leaking sensitive information from the browser's process memory back to the attacker.

The attack does not require any special privileges or user interaction beyond visiting the malicious page. The exploitation leverages Chrome's web rendering engine to trigger the memory corruption, making this a drive-by attack scenario that can be delivered through phishing links, malvertising, or compromised websites.

Detection Methods for CVE-2026-5869

Indicators of Compromise

• Unusual memory access patterns in Chrome browser processes related to WebML operations
• Browser crashes or unexpected behavior when visiting untrusted websites
• Anomalous network traffic from Chrome processes following visits to suspicious sites
• Memory dump artifacts showing evidence of heap corruption in WebML components

Detection Strategies

• Monitor Chrome process behavior for signs of memory corruption or abnormal heap operations
• Implement network-based detection for known malicious payloads targeting WebML vulnerabilities
• Deploy endpoint detection solutions capable of identifying heap overflow exploitation attempts
• Analyze browser crash reports for patterns consistent with CVE-2026-5869 exploitation

Monitoring Recommendations

• Enable Chrome's built-in crash reporting to capture exploitation attempts
• Monitor browser version compliance across the enterprise to identify unpatched installations
• Implement web content filtering to block access to known malicious sites hosting exploit code
• Configure SIEM alerts for Chrome-related security events and memory violations

How to Mitigate CVE-2026-5869

Immediate Actions Required

• Update Google Chrome to version 147.0.7727.55 or later immediately
• Enable automatic updates in Chrome to receive security patches promptly
• Review and restrict access to untrusted websites until patching is complete
• Consider temporarily disabling WebML features if available until patched

Patch Information

Google has addressed this vulnerability in Chrome version 147.0.7727.55. The security update includes fixes for the heap buffer overflow in the WebML component. Organizations should prioritize deploying this update across all managed endpoints.

For detailed patch information, refer to the Google Chrome Desktop Update. Additional technical details are available through the Chromium Issue Tracker Entry.

Workarounds

• Deploy browser isolation solutions to contain potential exploitation attempts
• Implement strict content security policies to limit exposure to malicious web content
• Use enterprise browser management to enforce version requirements
• Consider application whitelisting to restrict browser access to approved sites only

# Verify Chrome version is patched
google-chrome --version
# Expected: Google Chrome 147.0.7727.55 or higher

# Force Chrome update check (Linux)
sudo apt update && sudo apt install --only-upgrade google-chrome-stable

# Windows: Check via registry
reg query "HKLM\SOFTWARE\Google\Chrome" /v Version