CVE-2026-12443: Google Chrome Use After Free Vulnerability

CVE-2026-12443 Overview

CVE-2026-12443 is a use-after-free vulnerability [CWE-416] in the Web Authentication component of Google Chrome. The flaw affects all Chrome versions prior to 149.0.7827.155 on Windows, macOS, and Linux. A remote attacker can exploit the issue by serving a crafted HTML page that causes the browser to reference freed memory in the WebAuthn subsystem. Successful exploitation allows arbitrary code execution within the browser renderer process. Google classified the Chromium security severity as Critical, and the vulnerability requires user interaction to trigger.

Critical Impact
A remote attacker can execute arbitrary code in the Chrome renderer process by luring a user to a crafted HTML page that abuses the Web Authentication API.

Affected Products

Google Chrome versions prior to 149.0.7827.155
Chrome on Apple macOS
Chrome on Microsoft Windows and Linux distributions

Discovery Timeline

2026-06-17 - CVE-2026-12443 published to the National Vulnerability Database
2026-06-18 - Last updated in NVD database

Technical Details for CVE-2026-12443

Vulnerability Analysis

The vulnerability resides in the Web Authentication (WebAuthn) implementation in Chromium. WebAuthn enables passwordless and second-factor authentication using public-key credentials and hardware authenticators. The component manages credential objects, authenticator transports, and asynchronous callbacks between renderer and browser processes. A use-after-free condition arises when code retains a pointer to a WebAuthn object whose backing memory has already been released. Attackers can shape heap layout from JavaScript to place attacker-controlled data into the freed region, redirecting execution flow.

Root Cause

The defect is a classic memory lifetime mismanagement issue tracked under CWE-416. Object ownership in the WebAuthn pipeline is not preserved across asynchronous callback boundaries, leaving a dangling reference. When the dangling reference is dereferenced, the renderer operates on memory that has been reallocated for an unrelated purpose. Refer to the Chromium Issue Tracker Entry for the upstream technical record.

Attack Vector

Exploitation occurs over the network with low complexity but requires user interaction, such as visiting a malicious or compromised website. The attacker hosts a crafted HTML page that invokes WebAuthn APIs in a specific sequence to trigger the freed-object reuse. Combined with a sandbox escape, the issue can lead to full code execution on the host. See the Google Chrome Stable Update advisory for vendor details.

No public proof-of-concept exploit is currently available. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog at the time of publication.

Detection Methods for CVE-2026-12443

Indicators of Compromise

Chrome renderer process crashes referencing content::AuthenticatorImpl or related WebAuthn modules.
Outbound connections from Chrome to unfamiliar domains immediately after WebAuthn API calls in browsing telemetry.
Unexpected child processes spawned by chrome.exe following visits to untrusted pages.

Detection Strategies

Inventory installed Chrome versions across the fleet and flag any host running a build earlier than 149.0.7827.155.
Monitor browser process integrity using endpoint telemetry, focusing on anomalous memory access patterns and process injection from renderer children.
Correlate web proxy logs with endpoint events to identify users who reached suspicious pages invoking navigator.credentials.create or navigator.credentials.get.

Monitoring Recommendations

Forward Chrome crash dumps and Windows Error Reporting events to a centralized log platform for triage.
Track Chrome version compliance through software inventory tooling and alert on drift from the patched build.
Enable DNS and URL filtering logs to detect newly registered or low-reputation domains delivering HTML payloads.

How to Mitigate CVE-2026-12443

Immediate Actions Required

Update Google Chrome to version 149.0.7827.155 or later on Windows, macOS, and Linux endpoints.
Restart all Chrome instances after the update to ensure the patched binaries are loaded.
Validate that managed browser deployments (Chrome Enterprise, MDM-pushed installs) are configured for automatic updates.

Patch Information

Google released the fix in Chrome Stable channel build 149.0.7827.155. Administrators can review the official patch notes in the Google Chrome Stable Update advisory. Chromium-based browsers that consume the upstream fix should also be updated when their vendors publish corresponding releases.

Workarounds

Restrict access to untrusted websites using web filtering or browser isolation until patching is complete.
Disable or restrict the WebAuthn API through enterprise browser policies on systems that cannot be updated immediately.
Apply the principle of least privilege so that browser compromise does not directly yield administrative access to the endpoint.

bash

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

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

# Verify the installed Chrome version on Windows (PowerShell)
(Get-Item "$Env:ProgramFiles\Google\Chrome\Application\chrome.exe").VersionInfo.ProductVersion