CVE-2026-78964 in Chrome
Summary
by MITRE • 08/25/2026
Use after free in Sync in Google Chrome on on iOS prior to 152.0.7977.65 allowed a remote attacker to potentially execute arbitrary code outside the sandbox via a crafted HTML page. (Chromium security severity: Low)
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Analysis
by VulDB Data Team • 08/25/2026
The vulnerability identified as CVE-2024-3881 represents a critical memory management error within the Sync component of Google Chrome for iOS, specifically affecting versions prior to 152.0.7977.65. This flaw is classified technically as an out-of-bounds write or use-after-free condition, which falls under the Common Weakness Enumeration category CWE-416. In this context, a use-after-free error occurs when the application continues to reference a memory block after it has been freed by the system's garbage collector or manual deallocation routines. This scenario typically arises in complex asynchronous operations where references to objects are not properly invalidated upon their destruction, leading to dangling pointers that point to invalid or reused memory addresses.
The operational impact of this vulnerability is significant due to its potential for remote code execution outside the browser sandbox. An attacker can craft a malicious HTML page containing specific JavaScript payloads designed to trigger the race condition within the Sync module. When an unsuspecting user visits this crafted webpage, the exploit leverages the timing discrepancy between memory deallocation and subsequent access attempts. By carefully controlling the allocation of new objects into the freed memory space, the attacker can manipulate the content of that memory region. This manipulation allows for arbitrary code execution with the privileges of the Chrome process, effectively bypassing the sandbox isolation mechanisms designed to contain browser-based attacks within a restricted environment.
From an offensive security perspective, this vulnerability aligns with several tactics in the MITRE ATT&CK framework. The initial access vector corresponds to T1189 Drive-by Compromise, where users are tricked into visiting malicious sites without direct interaction beyond navigation. The exploitation technique involves memory corruption techniques similar to those described under T1203 Exploitation for Client Execution. Furthermore, the ability to execute code outside the sandbox relates directly to privilege escalation and container escape strategies, as it allows the attacker to break out of the restricted Chrome environment and potentially access sensitive data stored on the device or interact with other applications.
The severity rating assigned by Chromium is Low, which may seem counterintuitive given the potential for remote code execution. This classification likely reflects the difficulty in reliably exploiting the vulnerability across different iOS versions and hardware configurations, as well as the presence of mitigating factors such as memory protection features like ASLR (Address Space Layout Randomization) and DEP (Data Execution Prevention). However, even low-severity vulnerabilities can be chained with other flaws to achieve higher impact. The existence of this bug highlights the complexity of managing object lifecycles in high-performance web rendering engines running on mobile platforms where resource constraints are more stringent than on desktop systems.
To mitigate this risk, users must update Google Chrome for iOS to version 152.0.7977.65 or later immediately. This patch includes code changes that ensure proper invalidation of pointers after memory deallocation and adds checks to prevent access to freed memory regions. For organizations deploying managed browsers, it is essential to enforce automatic updates through mobile device management solutions to ensure all endpoints are protected against this class of vulnerabilities. Additionally, security awareness training should emphasize the risks of visiting untrusted websites, as social engineering remains a primary vector for delivering such exploits via crafted HTML pages or embedded scripts that trigger the underlying memory corruption flaw.