CVE-2026-78958 in Chrome
Summary
by MITRE • 08/26/2026
Uninitialized resource in Skia in Google Chrome prior to 152.0.7977.65 allowed a remote attacker who had compromised the renderer process to potentially obtain cross-origin data via a crafted HTML page. (Chromium security severity: Medium)
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 08/26/2026
The vulnerability identified within the Skia graphics library, which serves as the core 2D graphics engine for Google Chrome prior to version 152.0.7977.65, represents a critical failure in memory management and state initialization. This flaw is classified under CWE-457, which denotes the use of an uninitialized variable or resource. In the context of browser architecture, Skia handles complex rendering tasks such as drawing text, images, and vector graphics on web pages. When the engine processes specific graphical operations triggered by a crafted HTML page, it fails to properly initialize certain internal resources before they are accessed or utilized for data retrieval operations. This oversight creates a scenario where memory locations containing stale or arbitrary data from previous allocations may be read instead of expected zeroed-out or correctly initialized values.
The operational impact of this vulnerability is significant due to the potential for cross-origin data leakage, which directly undermines the browser's security model based on the Same-Origin Policy. Although the attacker must first compromise the renderer process, typically achieved through a separate initial exploit such as a remote code execution flaw in JavaScript or another component, the existence of this uninitialized resource allows for privilege escalation within that sandboxed environment. By crafting an HTML page that triggers specific rendering paths involving Skia, an attacker can manipulate the browser to read memory contents from other origins. This could lead to the exfiltration of sensitive information such as session cookies, authentication tokens, or private user data stored in local storage across different domains, effectively breaking the isolation boundaries intended to protect user privacy and security.
From a threat modeling perspective, this vulnerability aligns with ATT&CK technique T1059, specifically command and script interpretation if leveraged for further exploitation, but more critically it relates to data exfiltration techniques where sensitive information is gathered from local system resources. The severity of the issue is rated as Medium by Chromium security standards because while it requires a pre-existing compromise of the renderer process, its ability to facilitate cross-origin data theft makes it a valuable tool in post-exploitation phases for attackers aiming to maximize the value of an initial foothold. It highlights the importance of rigorous memory safety checks within high-performance graphics libraries that are deeply integrated into browser security boundaries.
Mitigation strategies primarily involve applying the official patch provided by Google Chrome, which updates Skia to ensure all resources are correctly initialized before use. For organizations unable to immediately update their browsers, network-level controls such as strict Content Security Policy headers can help mitigate some risks associated with cross-origin data access, although they do not fix the underlying memory flaw. Developers integrating Skia or similar graphics libraries into other applications should conduct thorough code audits focusing on resource initialization sequences and implement static analysis tools capable of detecting uninitialized variable usage to prevent similar vulnerabilities in future releases. Regular security updates and adherence to secure coding practices are essential to maintaining the integrity of browser-based environments against such sophisticated memory-related exploits.