CVE-2026-78984 in Chrome
Summary
by MITRE • 08/26/2026
Uninitialized resource in GPU in Google Chrome prior to 152.0.7977.65 allowed a remote attacker who had compromised the renderer process to potentially read memory outside the sandbox via a crafted HTML page. (Chromium security severity: Medium)
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Analysis
by VulDB Data Team • 08/26/2026
The vulnerability identified as an uninitialized resource in the GPU subsystem of Google Chrome prior to version 152.0.7977.65 represents a critical failure in state management within the browser's graphics processing unit interface. This flaw arises when specific graphical operations are initiated without proper initialization of underlying data structures or memory buffers allocated for rendering tasks. In modern web browsers, the GPU process operates with elevated privileges compared to the renderer processes that handle untrusted content from websites. The architecture relies on strict sandboxing to isolate potentially malicious code executed in renderers from sensitive system resources and user data. When an uninitialized resource is accessed, it can lead to undefined behavior where memory addresses are read or written without validation against allocated bounds or valid state contexts.
From a technical perspective, this issue falls under the category of improper initialization of variables or resources, which aligns with CWE-908 in the Common Weakness Enumeration database. The core mechanism involves the GPU driver or software abstraction layer receiving commands from a compromised renderer process via IPC (Inter-Process Communication). If these commands trigger operations that rely on previously allocated but uninitialized memory regions, the browser may expose raw memory contents to the attacker. This is particularly dangerous because it bypasses the sandbox boundaries designed to contain exploits within the low-privilege renderer environment. The lack of initialization means that residual data from previous operations or adjacent memory blocks can be inadvertently exposed, creating a side-channel for information disclosure.
The operational impact of this vulnerability allows a remote attacker who has already achieved code execution within the renderer process through other vectors such as JavaScript exploits to escalate their privileges and read arbitrary memory outside the sandbox. This capability effectively breaks the isolation model that protects users from malicious web content. An attacker could leverage this flaw to extract sensitive information stored in browser memory, including cookies, session tokens, passwords cached by autofill features, or cryptographic keys used for secure communications. The severity is rated as Medium because while it requires a pre-existing compromise of the renderer process, the ability to escape the sandbox significantly increases the potential damage and ease of exploitation compared to purely contained renderer-side vulnerabilities.
This type of vulnerability maps directly to several techniques in the MITRE ATT&CK framework, specifically those related to privilege escalation and data exfiltration from memory. Attackers might utilize this flaw as part of a multi-stage attack chain where initial access is gained via phishing or drive-by downloads, followed by renderer exploitation, and finally sandbox escape using this GPU uninitialized resource bug. The presence of such flaws highlights the complexity of maintaining robust isolation boundaries in complex software systems like web browsers that integrate multiple subsystems including networking, rendering, and hardware acceleration.
Mitigation for this vulnerability primarily involves updating Google Chrome to version 152.0.7977.65 or later where these initialization checks have been implemented. Developers should ensure that all GPU-related resources are explicitly initialized before being passed between processes or used in rendering pipelines. Implementing strict validation of memory states and employing fuzz testing on IPC interfaces can help detect such issues during development. For end-users, maintaining up-to-date browser versions is the most effective defense against exploitation attempts targeting these types of sandbox escape vulnerabilities. Security teams should also monitor for indicators of compromise that suggest active exploitation of renderer-side bugs leading to potential data leakage or further system intrusion.