CVE-2026-91716 in Chrome
Summary
by MITRE • 09/15/2026
Use after free in Auth in Google Chrome prior to 153.0.8010.47 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 • 09/15/2026
The vulnerability identified as a use-after-free condition within the authentication subsystem of Google Chrome prior to version 153.0.8010.47 represents a critical memory safety flaw that undermines the browser's core isolation mechanisms. This specific defect occurs when an object is deallocated from memory but continues to be referenced by other parts of the application, leading to undefined behavior upon subsequent access. In the context of web browsers, such errors are particularly dangerous because they can often be exploited to achieve arbitrary code execution with elevated privileges, effectively bypassing the sandbox environment designed to contain malicious content within a restricted security boundary. The classification of this issue as high severity by the Chromium team reflects its potential for remote exploitation and significant impact on system integrity.
From a technical perspective, use-after-free vulnerabilities typically arise from improper management of object lifecycles in C++ based codebases like Chromium. When an attacker crafts a malicious HTML page containing specific JavaScript or embedded content that triggers this race condition or logic error, they can manipulate the memory state to point freed heap chunks toward controlled data structures. This manipulation allows for arbitrary read and write operations within the browser process space. By carefully constructing the payload, an adversary can overwrite function pointers or virtual table entries, thereby gaining control over program execution flow. The exploitation of this flaw enables a remote attacker to execute arbitrary code outside the sandbox, which is the primary defense against web-based attacks. This bypass allows the malicious code to interact directly with the underlying operating system, potentially leading to full device compromise, data exfiltration, or installation of persistent malware.
The operational impact of this vulnerability extends beyond individual user sessions to broader organizational security postures if deployed in enterprise environments using managed browsers. An attacker leveraging this flaw can bypass sandbox restrictions that are intended to limit the damage caused by compromised web pages. This means that a simple visit to a malicious website, or even an ad served on a legitimate site containing exploit code, could result in complete system takeover without any user interaction beyond loading the page. The ability to execute code outside the sandbox negates many of the security benefits provided by modern browser architectures, making this vulnerability a high-priority target for threat actors seeking initial access vectors against targeted networks or individuals.
Mitigation strategies primarily involve immediate patching through updating Google Chrome to version 153.0.8010.47 or later, which includes fixes for the memory management logic in the authentication module. Organizations should ensure that automatic update mechanisms are enabled and monitored to prevent exposure during the window between vulnerability disclosure and remediation. Additionally, deploying browser isolation solutions or web filtering technologies can provide an additional layer of defense by preventing access to known malicious domains before they reach the vulnerable client application. Security teams should also monitor for indicators of compromise associated with exploitation attempts, such as unusual process spawning patterns from Chrome processes that deviate from normal behavior profiles defined in endpoint detection and response systems.
This vulnerability aligns with Common Weakness Enumeration identifier CWE-416, which describes use after free errors resulting from improper memory management practices. In terms of the MITRE ATT&CK framework, this flaw facilitates techniques related to initial access via exploit public applications or defense evasion through sandbox escape. The exploitation path typically involves crafting a malicious web page that triggers the vulnerability upon rendering, allowing the attacker to transition from a restricted browser context to an unrestricted execution environment on the host system. Understanding these mappings helps security professionals prioritize remediation efforts and align their defensive controls with established industry standards for mitigating memory corruption vulnerabilities in complex software ecosystems like modern web browsers.