CVE-2026-102329 in Chrome
Summary
by MITRE • 09/29/2026
Cross-site scripting in WebUI in Google Chrome prior to 154.0.8037.92 allowed a remote attacker to bypass web origin policy into a privileged page via a crafted HTML page. (Chromium security severity: High)
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Analysis
by VulDB Data Team • 09/29/2026
The vulnerability described constitutes a cross-site scripting flaw within the WebUI component of Google Chrome, specifically affecting versions prior to 154.0.8037.92. This issue stems from an improper validation or sanitization mechanism that fails to adequately neutralize user-supplied input before it is processed by the browser's rendering engine. When a remote attacker constructs and hosts a malicious HTML page containing specially crafted script payloads, they can exploit this weakness to inject executable code into the context of privileged pages within the Chrome WebUI framework. The severity of this vulnerability is classified as High because it allows for significant manipulation of the user interface and potentially sensitive internal browser functions that are typically shielded from standard web content by origin policies.
From a technical perspective, the core flaw lies in the failure to enforce strict separation between untrusted external data and trusted privileged contexts. WebUI pages often handle critical configuration settings or diagnostic information, operating under higher privilege levels than typical third-party websites. The attacker's crafted HTML page leverages this trust boundary breach by tricking the browser into executing arbitrary JavaScript within these elevated environments. This bypass of web origin policies is particularly dangerous because it allows code that should be confined to a sandboxed tab context to interact with internal browser components, potentially reading or modifying state data that normal websites are prohibited from accessing.
The operational impact of this vulnerability extends beyond simple script execution in an isolated frame. By achieving cross-origin access into privileged pages, the attacker can perform actions such as stealing sensitive configuration details, manipulating user settings without consent, or using the elevated privileges to launch further attacks against other parts of the browser ecosystem. This could lead to unauthorized data exfiltration, session hijacking if cookies are accessible within that context, or even remote code execution depending on subsequent exploitation chains involving other vulnerabilities in the rendering engine. The ability to bypass origin policies fundamentally undermines the security model that protects users from malicious web content, eroding trust in the browser's isolation mechanisms.
Mitigation strategies primarily involve immediate software updates to address the root cause of the input validation failure. Users and administrators must upgrade Google Chrome to version 154.0.8037.92 or later, where these specific WebUI sanitization issues have been resolved through enhanced filtering rules and stricter origin checks for privileged interfaces. In environments where immediate patching is not feasible, network-level controls such as web application firewalls can be configured to detect and block requests containing known malicious script patterns targeting Chrome's internal endpoints. Additionally, enforcing strict Content Security Policy headers on any custom WebUI implementations developed by organizations using the Chromium engine can provide an additional layer of defense against injection attacks.
This vulnerability aligns with CWE-79, which categorizes improper neutralization of input during web page generation as a cross-site scripting weakness. It also maps to MITRE ATT&CK techniques related to client-side evasion and privilege escalation within browser contexts, specifically those involving the abuse of trusted applications or interfaces. The exploitation vector relies on social engineering or drive-by download tactics where users are directed to malicious sites that trigger the vulnerability automatically upon page load. Understanding this attack path highlights the importance of maintaining up-to-date browsers and implementing robust input validation practices in all web-facing components interacting with privileged browser APIs.