CVE-2026-17778: Google Chrome Use After Free Vulnerability

CVE-2026-17778 Overview

CVE-2026-17778 is a use-after-free vulnerability [CWE-416] in the Extensions component of Google Chrome. The flaw affects Chrome versions prior to 151.0.7922.72. A remote attacker can trigger the condition by convincing a user to install or load a crafted Chrome Extension. Successful exploitation permits arbitrary code execution inside the Chrome sandbox. Chromium rates the security severity as Medium.

Critical Impact
Attackers who deliver a crafted extension can execute arbitrary code within the Chrome sandbox, providing a foothold for further chained exploitation targeting sandbox escapes or privilege escalation.

Affected Products

Google Chrome for Desktop versions prior to 151.0.7922.72
Chromium-based browsers incorporating the vulnerable Extensions component
Environments permitting installation of unvetted Chrome Extensions

Discovery Timeline

2026-07-30 - CVE-2026-17778 published to NVD
2026-07-30 - Last updated in NVD database

Technical Details for CVE-2026-17778

Vulnerability Analysis

The issue is a use-after-free defect in Chrome's Extensions subsystem. Use-after-free conditions occur when a program continues to reference memory after it has been released. An attacker who controls the timing of allocation and deallocation can place attacker-controlled data into the freed region. Subsequent dereferences then operate on adversary-influenced memory, enabling control-flow hijacking or arbitrary write primitives.

In this case, the vulnerable code path is reachable through a crafted Chrome Extension. Execution occurs inside the Chrome sandbox, which limits direct access to the host operating system. However, in-sandbox code execution is commonly chained with a separate sandbox escape to achieve full system compromise.

Root Cause

The root cause is object lifetime mismanagement within the Extensions component. A referenced object is freed while an outstanding pointer remains reachable, and later use of that dangling pointer allows the attacker's extension to influence execution. Refer to the Chromium Issue Tracker Entry for engineering details as they become public.

Attack Vector

Exploitation requires the victim to install a malicious extension or load a crafted extension package. Delivery vectors include social engineering, supply-chain compromise of legitimate extensions, enterprise policy misconfiguration, or side-loading of unpacked extensions. See the Google Chrome Release Update for the vendor's patch announcement.

No verified public proof-of-concept code is available for this vulnerability. Technical details will be described in prose only; consult the vendor advisory for authoritative information.

Detection Methods for CVE-2026-17778

Indicators of Compromise

Installation of Chrome Extensions from sources outside the Chrome Web Store or approved enterprise catalogs
Chrome renderer or extension process crashes with signatures consistent with heap corruption or use-after-free
Unexpected child processes or network connections originating from chrome.exe extension host processes

Detection Strategies

Inventory installed Chrome Extensions across managed endpoints and compare against an approved allowlist
Alert on Chrome versions below 151.0.7922.72 reported by asset management or endpoint telemetry
Monitor for extension installations that request broad host permissions such as <all_urls> or debugger

Monitoring Recommendations

Ingest Chrome browser telemetry, extension inventory, and process-creation events into a centralized data lake for correlation
Track outbound connections from browser child processes to unusual domains or IP addresses
Review Chrome crash reports for signatures matching Extensions subsystem faults

How to Mitigate CVE-2026-17778

Immediate Actions Required

Update Chrome to version 151.0.7922.72 or later on all managed and unmanaged endpoints
Audit currently installed extensions and remove any that are unnecessary or untrusted
Enforce an extension allowlist through Chrome enterprise policy to block side-loading

Patch Information

Google addressed CVE-2026-17778 in Chrome Stable channel version 151.0.7922.72. Details are published in the Google Chrome Release Update. Enterprise administrators should validate deployment through Chrome Browser Cloud Management or equivalent configuration management tooling.

Workarounds

Configure the ExtensionInstallAllowlist and ExtensionInstallBlocklist policies to restrict extensions to a vetted set
Disable developer mode extensions using the DeveloperToolsAvailability policy where feasible
Educate users about the risk of installing extensions from unofficial sources

bash

# Configuration example: Chrome enterprise policy (Linux JSON policy file)
# /etc/opt/chrome/policies/managed/extensions.json
{
  "ExtensionInstallBlocklist": ["*"],
  "ExtensionInstallAllowlist": [
    "aapocclcgogkmnckokdopfmhonfmgoek"
  ],
  "DeveloperToolsAvailability": 2
}