CVE-2026-7991: Google Chrome Use After Free Vulnerability

CVE-2026-7991 Overview

CVE-2026-7991 is a use-after-free vulnerability in the user interface component of Google Chrome versions prior to 148.0.7778.96. The flaw allows a remote attacker who has already compromised the renderer process to execute arbitrary code inside the Chrome sandbox by serving a crafted HTML page. The issue is tracked under [CWE-416] and affects Chrome installations across Windows, macOS, and Linux. Google rated the underlying Chromium issue as Medium severity, while the National Vulnerability Database scored it 8.8 due to network exploitability and the high impact on confidentiality, integrity, and availability.

Critical Impact
Successful exploitation enables arbitrary code execution within the Chrome sandbox, providing attackers with a foothold for further sandbox escape attempts and broader system compromise.

Affected Products

Google Chrome versions prior to 148.0.7778.96
Microsoft Windows installations running vulnerable Chrome builds
Apple macOS installations running vulnerable Chrome builds
Linux distributions running vulnerable Chrome builds

Discovery Timeline

2026-05-06 - CVE-2026-7991 published to the National Vulnerability Database
2026-05-06 - Last updated in NVD database
2026-05 - Google released the fix in the Chrome Stable channel update for desktop

Technical Details for CVE-2026-7991

Vulnerability Analysis

The vulnerability resides in the UI component of Google Chrome and is classified as a use-after-free condition. A use-after-free occurs when a program continues to reference memory after that memory has been deallocated, allowing attackers to manipulate the freed region and influence subsequent code paths. In this case, the affected object lives within the browser's user interface subsystem, which handles rendering and interaction logic outside the sandboxed renderer.

Google's advisory states the bug allows a remote attacker who has already compromised the renderer process to execute arbitrary code inside a sandbox via a crafted HTML page. This positions the flaw as part of a multi-stage exploit chain rather than a standalone entry vector. Attackers typically pair such bugs with a renderer compromise to expand their capabilities within the browser process model.

Root Cause

The root cause is improper lifetime management of a UI object. When the object is freed, a dangling pointer or reference remains accessible to other code paths. Subsequent operations dereference that stale pointer, allowing an attacker who controls the freed allocation's contents to redirect execution flow. The Chromium fix landed in version 148.0.7778.96, with technical details tracked in the Chromium Issue Tracker Entry.

Attack Vector

Exploitation requires user interaction. The victim must visit or be redirected to a crafted HTML page under attacker control. The attacker first needs control of the renderer process, typically achieved through a chained renderer-side vulnerability. After establishing renderer control, the attacker triggers the UI use-after-free to escalate code execution capabilities within the sandbox boundary. The attack does not require authentication and is exploitable over the network.

The vulnerability mechanism is described in prose only because Google has not published exploitation code. See the Google Chrome Release Update for vendor-confirmed details.

Detection Methods for CVE-2026-7991

Indicators of Compromise

Chrome browser processes spawning unexpected child processes or writing executables to user-writable directories
Crash reports referencing UI component memory faults in Chrome versions earlier than 148.0.7778.96
Outbound connections from chrome.exe to newly registered or low-reputation domains following visits to untrusted pages

Detection Strategies

Inventory installed Chrome versions across the fleet and flag any host running a build prior to 148.0.7778.96
Monitor browser process telemetry for anomalous memory access patterns, abnormal crashes, and renderer-to-broker IPC anomalies
Correlate web proxy logs with endpoint telemetry to identify users visiting suspicious HTML payloads followed by Chrome process anomalies

Monitoring Recommendations

Enable centralized collection of Chrome crash dumps and review entries that reference UI subsystem faults
Track Chrome update compliance through enterprise management tooling and alert on stale installations
Apply behavioral identification rules to detect post-exploitation activity such as credential access or persistence attempts originating from browser processes

How to Mitigate CVE-2026-7991

Immediate Actions Required

Update Google Chrome to version 148.0.7778.96 or later on all Windows, macOS, and Linux endpoints
Verify automatic update settings are enabled and that browsers have actually restarted to apply the patch
Audit endpoint inventories to confirm no legacy or pinned Chrome installations remain in use

Patch Information

Google addressed CVE-2026-7991 in the Chrome Stable channel update for desktop, distributed as version 148.0.7778.96 and later. The fix corrects the object lifetime handling in the UI component to eliminate the dangling reference. Refer to the Google Chrome Release Update for the complete advisory and the Chromium Issue Tracker Entry for issue tracking metadata.

Workarounds

Restrict browsing to trusted sites through enterprise web filtering until patching is complete
Enforce site isolation and disable unnecessary Chrome extensions to reduce the attack surface available to renderer compromises
Apply application allowlisting to block unauthorized child processes spawned by Chrome

bash

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

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

# Verify installed Chrome version on Windows (PowerShell)
(Get-Item "C:\Program Files\Google\Chrome\Application\chrome.exe").VersionInfo.ProductVersion