CVE-2026-11640: Chrome Integer Overflow Sandbox Escape in libyuv

Technical summary

CVE-2026-11640 is an integer overflow vulnerability in libyuv, a color space conversion library used by Google Chrome. The flaw exists in versions prior to 149.0.7827.103 and is classified as CWE-472 (Use of Incompletely Initialized Variable). The vulnerability allows a compromised renderer process to escape the sandbox through a specially crafted HTML page. While the CVSS 3.1 score is 8.3 (HIGH), Chromium rates this as Critical severity due to its potential for sandbox escape—the culmination attack in multi-stage browser exploitation.

Business impact

For organizations relying on Chrome as a primary browser, this vulnerability represents a critical gap in layered defenses. A compromised renderer (via phishing, malvertising, or watering-hole attacks) can escalate to full system compromise, potentially exfiltrating sensitive data, installing persistent malware, or lateral moving within corporate networks. The attack chain requires prior compromise but the sandbox escape eliminates the last containment boundary. Organizations without rapid patching cycles face heightened risk of post-breach privilege escalation.

Affected systems

Google Chrome versions prior to 149.0.7827.103 are vulnerable. The vulnerability also affects host operating systems—Apple macOS, Linux, and Microsoft Windows—since successful exploitation bypasses per-OS sandbox implementations. Any deployment of affected Chrome versions on these platforms is at risk.

Exploitability

Exploitation requires a two-step process: first, the attacker must already have compromised the Chrome renderer process (via a separate browser exploit, XSS, or similar). Second, they deliver the crafted HTML page to trigger the integer overflow. The high complexity (AC:H in the CVSS vector) reflects this prerequisite, but once the renderer is compromised, the HTML delivery is straightforward. User interaction is required (UI:R), typically just visiting a malicious page. The attack does not require network access to the victim's system directly—it works via remote HTML delivery.

Remediation

Update Google Chrome to version 149.0.7827.103 or later immediately. This patch addresses the integer overflow in libyuv. Ensure auto-updates are enabled so users receive patches without manual intervention. No workarounds exist; patching is the only mitigation.

Patch guidance

1. Verify your Chrome version (Menu > Help > About Google Chrome auto-checks for updates). 2. Chrome will auto-update to 149.0.7827.103 or later and prompt restart; accept the update. 3. For enterprise deployments, use Chrome Policy to enforce auto-updates or push the update via your device management solution. 4. Confirm the patch version after restart via the About page. 5. If using Chromium-based browsers (Edge, Brave, etc.), verify those vendors have released equivalent patches and deploy accordingly.

Detection guidance

Endpoint Detection & Response (EDR) tools should monitor for: (1) Unusual child processes spawned by chrome.exe or chromium processes (sandbox escape indicator); (2) Unexpected system calls or kernel-level access initiated from Chrome (privilege elevation); (3) File system modifications or registry changes linked to Chrome process activity post-exploitation. Network detection is difficult since the payload is HTML delivered normally. Focus on post-compromise indicators: unexpected outbound connections, credential access, or process injection from the browser process.

Why prioritize this

Although the vulnerability requires prior renderer compromise (not direct remote code execution), the consequence—sandbox escape leading to full system compromise—is severe. Organizations should prioritize this patch in the same tier as critical RCE vulnerabilities because it completes the attack chain for multi-stage browser exploits that are commonplace in real-world campaigns. The combination of HIGH CVSS, Critical Chromium severity, and the prevalence of renderer exploits in the wild justifies urgent patching.

Risk score, explained

The CVSS 3.1 score of 8.3 reflects: (1) network-reachable attack vector (AV:N); (2) high attack complexity (AC:H) due to the renderer compromise prerequisite; (3) no privileges required beforehand (PR:N); (4) user interaction needed (UI:R, visiting the malicious page); (5) changed scope (S:C, escaping the sandbox boundary); (6) high impact on confidentiality, integrity, and availability (C:H/I:H/A:H). The score appropriately weighs the severity of full system compromise against the multi-stage attack requirement.

Frequently asked questions