CVE-2026-12466: Chrome WebRTC Heap Buffer Overflow (High Severity)

Technical summary

CVE-2026-12466 is a heap buffer overflow vulnerability (CWE-122) in the WebRTC implementation within Google Chrome on Windows. The flaw exists in versions prior to 149.0.7827.155. When processing specially crafted HTML containing malicious WebRTC data, the vulnerable code writes beyond allocated heap memory boundaries, corrupting adjacent data structures and enabling arbitrary code execution in the context of the Chrome process. The attack surface is broad because WebRTC negotiation can be triggered automatically or via user interaction with embedded media elements.

Business impact

A successful exploit grants an attacker the ability to execute arbitrary code with the privileges of the logged-in user. An attacker can steal credentials, exfiltrate sensitive documents, inject persistent malware, or pivot to internal network resources. For organizations where employees use Chrome as their primary browser, this vulnerability creates significant risk for data breach, intellectual property theft, and lateral movement into corporate systems.

Affected systems

Google Chrome versions before 149.0.7827.155 running on Microsoft Windows are vulnerable. Unpatched installations on Windows 7, Windows 10, Windows 11, Windows Server, and other Windows variants are at risk. Enterprise deployments relying on Chrome for productivity, development, or internal applications should prioritize assessment of their user base.

Exploitability

This vulnerability has a low attack complexity and requires only network access plus user interaction (visiting a webpage). No authentication is required. The CVSS 3.1 score of 8.8 (High) reflects the ease of exploitation and severity of impact. While not currently listed on the KEV catalog as of the modification date, the combination of high severity, low barriers to exploitation, and potential for widespread use makes it an attractive target for threat actors. Exploitation does not require zero-day sophistication once a working payload is developed.

Remediation

Organizations must prioritize updating Google Chrome to version 149.0.7827.155 or later on all Windows systems. Chrome's built-in auto-update feature typically rolls out patches within days, but administrators should verify deployment in managed environments. For organizations unable to immediately patch, temporary mitigations include disabling WebRTC in Chrome settings (chrome://settings/privacy), restricting access to untrusted websites via network controls, or transitioning critical tasks to alternative browsers until patching is complete.

Patch guidance

Update Google Chrome to 149.0.7827.155 or any subsequent stable release. In managed environments, use Chrome enterprise policies to enforce minimum version requirements and monitor update compliance. Verify patching through Chrome's about:chrome menu, which displays the installed version and indicates when updates are available. Test updates in a controlled environment before full rollout if you manage a large fleet. Monitor vendor security advisories for any post-patch issues or related WebRTC vulnerabilities.

Detection guidance

Detection at the network level is challenging because exploit traffic is encrypted HTTPS. Endpoint detection should focus on browser process anomalies: look for unusual child processes spawned from Chrome (chrome.exe), unexpected network connections from Chrome, or execution of payloads in the Chrome AppData directory. Behavioral monitoring for elevated privilege escalation attempts following WebRTC activities may surface exploitation attempts. Monitor Windows Event Logs for process creation events and unusual registry modifications. Consider deploying browser isolation or sandboxing technologies that can contain WebRTC exploitation.

Why prioritize this

This vulnerability merits urgent patching due to its high CVSS score (8.8), ease of exploitation, and severe impact. The combination of user interaction requirement (not 'zero-click') and widespread Chrome adoption means risk is high but not universally equal—organizations where users frequently visit external websites face greater exposure. The lack of complex exploitation barriers and the public disclosure create an environment where weaponized exploits may emerge quickly. Prioritize patching for all user-facing systems within 7–14 days.

Risk score, explained

CVSS 3.1 score of 8.8 reflects: (1) Network-accessible attack vector (AV:N); (2) Low attack complexity requiring no special conditions (AC:L); (3) No privileges required to trigger the flaw (PR:N); (4) Requirement for user interaction—clicking a link or visiting a webpage (UI:R); (5) Scope unchanged (the attacker does not break out to other security domains); (6) High impact on confidentiality, integrity, and availability (C:H/I:H/A:H) because code execution allows stealing data, modifying system state, or crashing the browser. The score appropriately weights the easy exploitation path against the severe impact.

Frequently asked questions