CVE-2026-79006 in Chrome
Summary
by MITRE • 08/26/2026
Protection mechanism failure in HttpsUpgrades in Google Chrome prior to 152.0.7977.65 allowed a remote attacker to bypass web origin policy via crafted network traffic. (Chromium security severity: Medium)
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Analysis
by VulDB Data Team • 08/26/2026
The vulnerability identified as a protection mechanism failure within the HTTPS upgrades component of Google Chrome, specifically in versions prior to 152.0.7977.65, represents a significant deviation from expected secure browsing behaviors. This flaw allows for the bypassing of web origin policies through the manipulation of crafted network traffic. The core issue lies in how the browser handles protocol upgrades and subsequent security checks during the initial connection phase or when redirecting between HTTP and HTTPS endpoints. When an attacker crafts specific network packets that exploit inconsistencies in these upgrade mechanisms, they can trick the browser into treating a malicious resource as if it originated from a trusted domain. This undermines the fundamental web isolation model that prevents scripts loaded from one origin from accessing data belonging to another, thereby creating a pathway for unauthorized cross-origin access.
From a technical perspective, this vulnerability is categorized under CWE-284, which describes Improper Access Control, and more specifically relates to CWE-913, where the system fails to properly enforce restrictions on actions taken by an actor with respect to objects or resources controlled by that actor. The attack vector involves manipulating network traffic to exploit race conditions or logic errors in how Chrome validates the origin of content after a protocol upgrade occurs. By sending specially crafted requests, an attacker can cause the browser to incorrectly associate sensitive cookies, local storage data, or DOM elements from one site with another malicious context. This bypass is particularly dangerous because it operates at the network and application layer intersection, making it difficult for traditional perimeter defenses like firewalls to detect without deep packet inspection capabilities that understand TLS handshake nuances and HTTP upgrade headers.
The operational impact of this vulnerability is severe in terms of data confidentiality and integrity. An attacker who successfully exploits this flaw can perform cross-site scripting attacks with elevated privileges or steal sensitive user information such as session tokens, authentication cookies, and personally identifiable information stored by web applications. This capability effectively neutralizes the Same-Origin Policy, which is a cornerstone of modern web security designed to isolate potentially malicious documents from sensitive data. In enterprise environments where employees access multiple internal and external services through Chrome, this vulnerability could lead to credential theft or session hijacking if users interact with compromised sites while authenticated on other critical platforms. The medium severity rating assigned by the Chromium team reflects the complexity required for exploitation but acknowledges the high potential impact once a successful attack is executed against an unpatched client.
Mitigation strategies must focus primarily on immediate software updates and network-level controls until all endpoints are patched to version 152.0.7977.65 or later. Administrators should enforce automatic update policies for Google Chrome across all organizational devices to ensure rapid remediation of known vulnerabilities. Additionally, implementing strict Content Security Policy headers in web applications can provide a layer of defense-in-depth by restricting the sources from which scripts and other resources are loaded, thereby reducing the attack surface even if the browser-level protection fails. Network security teams should also monitor for anomalous HTTP upgrade requests or unusual patterns in TLS handshakes that might indicate active exploitation attempts using crafted traffic designed to trigger this specific logic error.
This incident aligns with ATT&CK technique T1078, Valid Accounts, and potentially T1534, Internal Spearphishing if the initial vector involves social engineering leading users to malicious sites that exploit the browser flaw. It also relates to T1059, Command and Scripting Interpreter, as the ultimate goal is often to execute arbitrary code or exfiltrate data via scripts running in a trusted context. Security operations centers should prioritize monitoring for indicators of compromise associated with cross-origin request anomalies and ensure that endpoint detection systems are configured to flag unusual browser behavior indicative of origin policy bypasses. Regular vulnerability assessments and penetration testing focused on web application security controls will help identify similar implementation flaws before they can be exploited by threat actors seeking to leverage browser vulnerabilities for lateral movement or data theft within targeted networks.