CVE-2026-13919: Google Chrome Auth Bypass Vulnerability

CVE-2026-13919 Overview

CVE-2026-13919 is an insufficient policy enforcement vulnerability in the Extensions component of Google Chrome prior to version 150.0.7871.47. The flaw allows a remote attacker who has already compromised the renderer process to bypass site isolation using a crafted HTML page. Chromium engineers rated the security severity as Medium. The vulnerability is categorized under CWE-602: Client-Side Enforcement of Server-Side Security and affects the browser's ability to enforce security boundaries between origins.

Critical Impact
An attacker with a compromised renderer can escape site isolation, breaking the integrity boundary that separates web origins in Chrome and enabling cross-origin data access or tampering.

Affected Products

Google Chrome versions prior to 150.0.7871.47
Chromium-based browsers sharing the same Extensions policy enforcement code
Desktop Chrome Stable channel builds released before the June 2026 update

Discovery Timeline

2026-06-30 - CVE-2026-13919 published to NVD
2026-07-01 - Last updated in NVD database

Technical Details for CVE-2026-13919

Vulnerability Analysis

The vulnerability resides in the Extensions subsystem of Google Chrome. Chrome relies on site isolation to place documents from different sites into distinct renderer processes, preventing one origin from reading another's memory or DOM. The Extensions component fails to enforce this policy correctly under specific conditions triggered by a crafted HTML page. An attacker who has already exploited a separate flaw to compromise the renderer process can leverage this weakness to cross the site isolation boundary.

Because exploitation requires a pre-compromised renderer, this bug is typically chained with a prior renderer exploit such as a V8 type confusion or use-after-free. The result is loss of integrity across origins that should remain isolated. Confidentiality of cross-site data can be indirectly affected, though the primary CVSS impact rating targets integrity.

Root Cause

The root cause is client-side enforcement of a security decision that must be validated in a trusted browser process. Extension-related policy checks in the renderer accept state that a compromised renderer can forge. Because site isolation depends on the browser process authoritatively partitioning origins, any renderer-side shortcut becomes a bypass primitive. Chromium issue #511249430 tracks the fix.

Attack Vector

Exploitation is network-based and requires user interaction, typically visiting an attacker-controlled page. The attacker first compromises the renderer, then serves a crafted HTML page that triggers the extension policy flaw. Successful exploitation lets the attacker interact with resources belonging to other sites, defeating the isolation model. No verified public proof-of-concept is available at this time. See the Chromium security advisory for additional detail.

Detection Methods for CVE-2026-13919

Indicators of Compromise

Chrome browser processes running versions earlier than 150.0.7871.47 on endpoints with internet access
Unexpected extension activity or extension-hosted pages loading cross-origin frames outside declared host permissions
Renderer process crashes or sandbox anomalies preceding suspicious cross-origin network requests

Detection Strategies

Inventory installed Chrome versions across the fleet and flag any host below 150.0.7871.47
Monitor endpoint telemetry for Chrome child processes spawning unexpected children or making unusual outbound connections following extension activity
Correlate browser telemetry with proxy logs to identify anomalous cross-site requests originating from a single browsing session

Monitoring Recommendations

Enable enterprise browser reporting through Chrome Browser Cloud Management to track extension installs and version drift
Ingest browser and endpoint logs into a centralized analytics platform for behavioral correlation across renderer crashes and network activity
Alert on installation of unreviewed extensions from outside the Chrome Web Store or from side-loaded sources

How to Mitigate CVE-2026-13919

Immediate Actions Required

Update Google Chrome to version 150.0.7871.47 or later on all managed endpoints
Force-restart Chrome after the update so the patched binary is loaded into memory
Audit installed extensions and remove any that are unnecessary, unmaintained, or from untrusted publishers

Patch Information

Google addressed CVE-2026-13919 in Chrome Stable channel release 150.0.7871.47. The patch is delivered through the standard Chrome auto-update mechanism. Administrators can validate deployment by checking chrome://version on endpoints or by querying enterprise management consoles. Full release notes are published in the Chrome Releases blog.

Workarounds

Restrict extension installation using the ExtensionInstallAllowlist and ExtensionInstallBlocklist enterprise policies until patching completes
Deploy SitePerProcess policy to enforce strict site isolation on all managed browsers
Reduce user browsing risk by routing traffic through a filtering proxy that blocks known malicious sites hosting renderer exploits

bash

# Configuration example - enforce site isolation and restrict extensions via Chrome policy (Linux)
cat > /etc/opt/chrome/policies/managed/cve-2026-13919.json <<EOF
{
  "SitePerProcess": true,
  "IsolateOrigins": "https://*.example.com",
  "ExtensionInstallBlocklist": ["*"],
  "ExtensionInstallAllowlist": ["<approved-extension-id>"]
}
EOF