CVE-2026-13891: Google Chrome Privilege Escalation Flaw

CVE-2026-13891 Overview

CVE-2026-13891 is an input validation vulnerability [CWE-20] 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 escalate privileges through a crafted HTML page. Google classifies the Chromium security severity as Medium, while NVD scores the issue at 7.5.

The vulnerability affects Chrome across Windows, macOS, and Linux desktop platforms. Exploitation requires user interaction and high attack complexity, but successful abuse impacts confidentiality, integrity, and availability.

Critical Impact
A compromised renderer process can escalate privileges beyond the browser sandbox, potentially reaching higher-privileged browser contexts through the Extensions component.

Affected Products

Google Chrome prior to 150.0.7871.47
Chrome desktop on Microsoft Windows
Chrome desktop on Apple macOS and Linux

Discovery Timeline

2026-06-30 - CVE-2026-13891 published to NVD
2026-07-02 - Last updated in NVD database

Technical Details for CVE-2026-13891

Vulnerability Analysis

The vulnerability resides in Chrome's Extensions subsystem and stems from insufficient validation of untrusted input. An attacker who has already achieved code execution inside a renderer process can leverage this weakness to escalate privileges within the browser. Renderer compromise is typically the first stage of a Chrome exploit chain, and privilege escalation to a higher-trust process is the second stage required to escape the sandbox.

Exploitation requires user interaction, such as loading a crafted HTML page, and Chrome's threat model treats the renderer as untrusted. The Extensions layer, however, operates with elevated privileges relative to web content, making it a valuable target for chained exploits.

Root Cause

The root cause is improper input validation [CWE-20] in the Extensions component. Chrome fails to adequately sanitize or verify data crossing the boundary from the renderer process into extension-handling code paths. This allows attacker-controlled input to influence privileged logic that should only accept trusted values.

Attack Vector

The attack requires two conditions. First, the attacker must compromise the renderer process, typically through a separate memory corruption or logic bug. Second, the attacker delivers a crafted HTML page that interacts with the Extensions component to trigger the input validation failure. See the Chromium Issue #501631475 tracker for additional technical context.

No public proof-of-concept exploit is available, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog. The EPSS probability is 0.302%.

Detection Methods for CVE-2026-13891

Indicators of Compromise

Chrome browser processes running versions earlier than 150.0.7871.47 in the enterprise fleet.
Unexpected child processes spawned from chrome.exe or the renderer following interaction with untrusted HTML pages.
Anomalous extension installation, modification, or manifest changes not originating from the Chrome Web Store.

Detection Strategies

Monitor endpoint telemetry for Chrome renderer processes that spawn code execution outside expected sandbox boundaries.
Correlate browser process activity with subsequent file writes to extension directories or user profile paths.
Alert on outbound network connections from Chrome child processes to newly observed or low-reputation domains.

Monitoring Recommendations

Inventory installed Chrome versions across managed endpoints and flag any host below 150.0.7871.47.
Track extension inventory changes and enforce allowlists through enterprise policy.
Ingest Chrome browser and endpoint process telemetry into a centralized analytics platform for cross-host correlation.

How to Mitigate CVE-2026-13891

Immediate Actions Required

Update Google Chrome to version 150.0.7871.47 or later on all Windows, macOS, and Linux endpoints.
Force a browser restart after deployment to ensure the patched binary is loaded into memory.
Audit installed extensions and remove those not required for business operations.

Patch Information

Google released the fix in the Chrome Stable channel update documented in the Google Chrome Desktop Update advisory. Enterprises using managed Chrome deployments should verify update policies deliver 150.0.7871.47 or later to all users.

Workarounds

Restrict extension installation to an administrator-approved allowlist using Chrome enterprise policy ExtensionInstallAllowlist.
Disable third-party extensions on high-value systems until patches are deployed.
Apply strict site isolation and enforce user training against opening untrusted HTML content.

bash

# Configuration example: enforce Chrome extension allowlist via policy
# Windows (registry)
reg add "HKLM\Software\Policies\Google\Chrome\ExtensionInstallBlocklist" /v 1 /t REG_SZ /d "*" /f
reg add "HKLM\Software\Policies\Google\Chrome\ExtensionInstallAllowlist" /v 1 /t REG_SZ /d "<approved-extension-id>" /f

# macOS / Linux (managed policy JSON)
# /etc/opt/chrome/policies/managed/extensions.json
{
  "ExtensionInstallBlocklist": ["*"],
  "ExtensionInstallAllowlist": ["<approved-extension-id>"]
}