CVE-2026-78939 in Chrome
Summary
by MITRE • 08/25/2026
Use after free in Chromecast in Google Chrome prior to 152.0.7977.65 allowed a remote attacker who had compromised the renderer process 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 • 08/25/2026
The vulnerability identified as a use-after-free flaw within Google Chrome prior to version 152.0.7977.65 represents a critical memory management error that compromises the integrity of the browser's sandboxing mechanisms. This specific defect is located in the Chromecast component, which handles media casting and streaming functionalities integrated into the Chromium engine. The core technical issue arises when an object allocated on the heap is freed while there are still active references to it held by other parts of the application. In this context, a crafted HTML page can trigger conditions where memory is deallocated prematurely or incorrectly managed during the processing of media-related data structures. When subsequent code attempts to access these dangling pointers, it results in undefined behavior that an attacker can exploit to manipulate program flow and gain unauthorized control over system resources.
The operational impact of this vulnerability is severe due to its potential for remote code execution outside the browser's security sandbox. Typically, Chrome employs a multi-process architecture where renderer processes are isolated from sensitive system operations through strict sandboxing policies designed to limit the damage if a process is compromised. However, because this use-after-free flaw allows an attacker who has already gained control over the renderer process via a malicious webpage to escalate privileges and execute arbitrary code in higher-privilege contexts, it effectively bypasses these protective boundaries. This means that once a user visits a specially crafted website or clicks on a manipulated link, the browser's internal state can be corrupted to allow the execution of native machine code with elevated permissions, potentially leading full system compromise depending on the privileges under which the browser is running.
From a threat modeling perspective, this vulnerability aligns closely with Common Weakness Enumeration (CWE) category CWE-416, which defines use-after-free errors as situations where memory is accessed after it has been freed. This type of flaw is frequently leveraged in exploit chains to achieve arbitrary code execution by overwriting function pointers or virtual table entries within the corrupted memory space. Furthermore, this incident maps directly to MITRE ATT&CK technique T1203, which covers Exploitation for Client Execution, as well as techniques related to sandbox escape such as those found under privilege escalation vectors. The ability to break out of the renderer process isolation is particularly dangerous because it negates one of the primary defense-in-depth strategies employed by modern web browsers against drive-by download attacks and cross-site scripting exploits that aim to achieve code execution.
Mitigation for this vulnerability requires immediate action from both end-users and system administrators. Users should update Google Chrome to version 152.0.7977.65 or later, which contains the necessary patches to correct the memory management logic within the Chromecast component. For organizations managing large fleets of devices, deploying browser updates through centralized configuration management tools is essential to ensure consistent protection across all endpoints. Additionally, security teams should monitor for indicators of compromise associated with drive-by download campaigns that target outdated browsers and consider implementing application control policies or strict content security policies to restrict the execution of untrusted scripts within the browser environment. Regular patching cycles remain the most effective defense against such memory corruption vulnerabilities that are actively exploited in the wild by sophisticated threat actors seeking initial access through web-based vectors.