CVE-2026-102309 in Chrome
Summary
by MITRE • 09/29/2026
Use after free in FullScreen in Google Chrome prior to 154.0.8037.92 allowed a remote attacker to execute arbitrary code outside the sandbox via a crafted HTML page. (Chromium security severity: High)
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Analysis
by VulDB Data Team • 09/29/2026
The vulnerability identified as a use-after-free condition within the FullScreen component of Google Chrome prior to version 154.0.8037.92 represents a critical memory management error that compromises the integrity and confidentiality of user data. This flaw arises when the browser fails to properly manage the lifecycle of objects associated with full-screen mode operations, specifically allowing access to memory regions after they have been deallocated by the system. In modern web browsers, such as Chrome which utilizes the Chromium engine, complex interactions between JavaScript execution contexts and native C++ components are frequent. When a webpage triggers full-screen functionality, it initiates specific rendering pipelines and state management routines. If an attacker crafts a malicious HTML page that manipulates these states in a precise sequence, they can exploit the timing gap where memory is freed but pointers to that memory remain valid within certain execution contexts. This scenario allows for arbitrary read or write operations on heap memory, which serves as the foundation for more severe exploitation techniques.
From a technical perspective, this vulnerability aligns with CWE-416, Use After Free, which describes situations where software continues to use a pointer after it has been freed. The operational impact of such a flaw is significant because Chrome employs a multi-process architecture designed to isolate web content within sandboxes. These sandboxes restrict the privileges of renderer processes to prevent malicious code from accessing sensitive system resources or user data directly. However, memory corruption vulnerabilities like this one can potentially allow an attacker to bypass these sandbox boundaries if they can achieve arbitrary code execution with sufficient privilege levels. By carefully crafting heap layouts and exploiting the use-after-free condition, a remote attacker could execute arbitrary commands on the victim's machine outside the restrictive environment of the browser sandbox. This effectively neutralizes one of the primary defense mechanisms employed by modern browsers to protect users from web-based attacks.
The exploitation vector for this vulnerability is classified as remote, meaning that an attacker does not need physical access or prior authentication on the target system. Instead, success relies entirely on tricking a user into visiting a specially crafted webpage hosted on a malicious server. This aligns with ATT&CK technique T1059, Command and Scripting Interpreter, specifically within the context of web-based attacks where JavaScript is used to facilitate further exploitation steps such as downloading additional payloads or establishing command-and-control channels. The severity rating of High reflects the potential for code execution without user interaction beyond clicking a link or loading a page, although modern browsers often include mitigations like heap hardening and ASLR that may complicate successful exploitation in real-world scenarios. Nevertheless, the existence of such a flaw indicates a serious lapse in memory safety practices within the affected component.
Mitigation strategies for this vulnerability primarily involve immediate software updates to ensure users are running version 154.0.8037.92 or later of Google Chrome, where the issue has been resolved through improved memory management logic and stricter validation checks during full-screen state transitions. Organizations should enforce automated patching policies to minimize the window of exposure for their workforce. Additionally, security awareness training can help users recognize suspicious links that might lead to malicious pages designed to exploit browser vulnerabilities. While technical controls like endpoint detection and response systems may detect anomalous behavior resulting from exploitation attempts, they are not a substitute for timely software updates. The resolution underscores the importance of rigorous code review processes and static analysis tools in identifying memory safety issues before deployment, ensuring that complex web features do not introduce exploitable flaws into the browser core.