CVE-2026-78969 in Chrome
Summary
by MITRE • 08/26/2026
Uninitialized resource in Video in Google Chrome prior to 152.0.7977.65 allowed a remote attacker to read memory inside 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 issue within the video processing subsystem of Google Chrome prior to version 152.0.7977.65 represents a significant class of memory safety defects that can lead to information disclosure attacks. This flaw stems from improper initialization of internal data structures or buffers used during the handling of multimedia content, specifically when parsing and rendering video streams via HTML pages. In modern web browsers like Chrome, complex media processing pipelines are employed to decode various video formats efficiently. When a crafted HTML page triggers specific code paths within this pipeline, the application fails to properly initialize certain memory regions before they are accessed or read by subsequent operations. This lack of initialization means that these memory locations may contain residual data from previous allocations, which can include sensitive information such as stack variables, heap metadata, or even parts of other processes if sandbox boundaries are not strictly enforced at this specific layer.
From a technical perspective, the core issue lies in the failure to zero out or explicitly set default values for resources allocated during video decoding operations. When an attacker constructs a malicious HTML page containing specially crafted media elements or scripts that interact with these video components, they can trigger conditions where uninitialized memory is read and potentially returned as part of the application's output or internal state. This scenario aligns closely with CWE-457, which describes the use of an uninitialized variable, and CWE-908, regarding the use of uninitialized pointer. The severity is classified as medium by Chromium security standards because while it allows for out-of-bounds reads within the sandboxed renderer process, direct code execution is not immediately guaranteed. However, reading arbitrary memory from inside the sandbox provides attackers with valuable intelligence about the browser's internal state, which can be leveraged to bypass other security mitigations or facilitate further exploitation steps such as heap spraying analysis or ASLR bypass techniques.
The operational impact of this vulnerability centers on the potential for remote information disclosure without user interaction beyond visiting a malicious webpage. An attacker hosting a crafted HTML page could exploit this flaw when a victim visits it, leading to the leakage of memory contents that might contain cookies, session tokens, private keys, or other sensitive data stored in browser memory. Although Chrome employs robust sandboxing mechanisms designed to isolate renderer processes from the operating system and user profile, vulnerabilities within these isolated environments can still compromise confidentiality by allowing one process to read another's memory if proper isolation checks are bypassed through uninitialized resource access patterns. This type of attack falls under the MITRE ATT&CK technique T1005, which covers Data from Local System, specifically focusing on application data harvesting via local input capture or memory scraping techniques enabled by browser-side flaws.
Mitigation strategies primarily involve updating to a patched version of Google Chrome where this initialization logic has been corrected to ensure all video-related resources are properly initialized before use. Developers and security teams should also enforce strict code review practices that emphasize static analysis tools capable of detecting uninitialized variable usage in C++ projects, which form the backbone of Chromium's architecture. Additionally, enabling advanced browser security features such as Site Isolation can help limit the blast radius of any successful exploitation by ensuring that sensitive data is not shared across different origins unnecessarily. Regular patching cycles and monitoring for new CVEs related to media processing components are essential practices for maintaining a secure browsing environment against evolving web-based attack vectors.