CVE-2026-11659: Google Chrome RCE Vulnerability

CVE-2026-11659 Overview

CVE-2026-11659 is an integer overflow vulnerability in the UI component of Google Chrome on Linux. The flaw affects versions prior to 149.0.7827.103 and enables a remote attacker to potentially perform a sandbox escape through a crafted HTML page. Chromium engineers classified the security severity as High, while the National Vulnerability Database scored the issue at 9.6 (Critical) under CVSS 3.1. The vulnerability maps to [CWE-20: Improper Input Validation]. Exploitation requires user interaction, typically through visiting a malicious web page, but does not require authentication or privileges.

Critical Impact
A successful exploit allows a remote attacker to escape the Chrome sandbox on Linux, breaking out of the browser's primary security boundary and gaining the ability to influence the host system.

Affected Products

Google Chrome on Linux prior to 149.0.7827.103
Chromium-based browsers sharing the affected UI code path
Linux desktop environments running vulnerable Chrome builds

Discovery Timeline

2026-06-09 - CVE-2026-11659 published to NVD
2026-06-09 - Last updated in NVD database
2026-06-11 - EPSS score recorded at 0.106% (percentile 28.259)

Technical Details for CVE-2026-11659

Vulnerability Analysis

The vulnerability resides in Chrome's UI subsystem, where an integer overflow occurs during processing influenced by content from a crafted HTML page. When the affected arithmetic operation exceeds the bounds of its integer type, the resulting wraparound produces incorrect size or index values consumed by downstream logic. That miscalculation allows an attacker to manipulate UI-related state in ways the developers did not anticipate.

Because the affected code participates in privileged browser operations, the integer overflow can be leveraged to escape the renderer sandbox. A sandbox escape promotes a web-origin attacker from constrained renderer privileges to broader browser-process privileges on the host. The CVSS scope change reflects this cross-boundary impact, and the attack vector remains network-based since delivery only requires the victim to load attacker-controlled HTML.

Root Cause

The root cause is improper input validation [CWE-20] of values that feed into an arithmetic computation in the UI layer. The code fails to verify that operands or results remain within the representable range of the target integer type. The overflow corrupts derived values such as offsets, lengths, or buffer sizes used by Chrome's UI handling logic.

Attack Vector

An attacker hosts a crafted HTML page and convinces a victim running a vulnerable Chrome version on Linux to load it. User interaction is required, consistent with UI:R in the CVSS vector. Once loaded, the page triggers the overflow condition in the UI component and chains the resulting memory or state corruption into a sandbox escape primitive.

No public proof-of-concept code, ExploitDB entry, or CISA KEV listing exists for this CVE at the time of publication. The vulnerability is not currently known to be exploited in the wild. Technical details remain available through the Chromium Issue Tracker Entry and the Google Chrome Stable Update advisory.

Detection Methods for CVE-2026-11659

Indicators of Compromise

Chrome renderer or browser process crashes on Linux endpoints with stack frames inside UI components
Unexpected child processes spawned by the Chrome browser process following navigation to untrusted pages
Outbound connections from Chrome helper processes to domains not associated with normal browsing activity
Linux endpoints running Chrome versions below 149.0.7827.103 identified through software inventory

Detection Strategies

Inventory Chrome installations on Linux fleets and flag versions earlier than 149.0.7827.103 for remediation tracking
Monitor for anomalous process lineage where Chrome processes execute shells, package managers, or scripting interpreters
Correlate browser crash telemetry with subsequent process creation or file write activity to surface post-exploitation behavior

Monitoring Recommendations

Collect Chrome stable channel release notes and map CVE identifiers to deployed versions on a recurring schedule
Forward Linux audit logs covering execve, clone, and network syscalls from Chrome processes to a centralized analytics platform
Alert on Chrome processes accessing sensitive paths such as ~/.ssh, /etc, or credential stores outside expected behavior

How to Mitigate CVE-2026-11659

Immediate Actions Required

Update Google Chrome on all Linux endpoints to version 149.0.7827.103 or later using the distribution's package manager
Restart Chrome after the update so the patched binaries replace running processes
Audit Chromium-derived browsers on Linux for vendor patches that incorporate the upstream fix

Patch Information

Google released the fix in the stable channel update documented in the Google Chrome Stable Update advisory. Linux users should install Chrome 149.0.7827.103 or any later stable build. Additional engineering context appears in the Chromium Issue Tracker Entry.

Workarounds

Restrict browsing on unpatched Linux hosts to trusted internal sites using DNS or proxy policy until the update is applied
Deploy Chrome enterprise policies that disable or restrict features known to surface the affected UI code paths where feasible
Use site isolation and per-profile sandboxing settings to reduce the impact of a successful renderer compromise

bash

# Configuration example: verify and update Chrome on Debian/Ubuntu Linux
dpkg -l | grep google-chrome-stable
sudo apt-get update
sudo apt-get install --only-upgrade google-chrome-stable
google-chrome --version  # must report 149.0.7827.103 or later