Description

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)

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "9.6",
  "pubDate": "2026-08-25T21:17:52.507Z",
  "pubdate": "2026-08-25T21:17:52.507Z",
  "executiveSummary": "A Use-After-Free (UAF) vulnerability exists within the Sync component of Google Chrome for iOS, identified in versions prior to 152.0.7977.65. The flaw originates from improper memory management during synchronization operations, potentially leading to memory corruption.\nA remote attacker can leverage this vulnerability by enticing a user to navigate to a specifically crafted HTML page. Successful exploitation enables the execution of arbitrary code, bypassing existing sandbox security controls to achieve unauthorized command execution on the host device.\nDespite the 'Low' Chromium security severity rating, the ability to escape the browser sandbox poses significant risks, including potential data exfiltration or unauthorized system interaction. No user authentication or elevated privileges are required for an attacker to initiate the exploit sequence; the primary requirement is user interaction with malicious web content.\nGiven the nature of the UAF condition, the impact is critical for affected users, as successful exploitation can undermine the integrity and confidentiality of the iOS device environment. Organizations and users are strongly advised to update to version 152.0.7977.65 or higher to resolve the underlying memory safety defect.",
  "technicalDetails": "The vulnerability resides within the Sync component of the Chromium codebase as integrated into Google Chrome for iOS. Use-after-free vulnerabilities occur when an application continues to utilize a pointer to a memory location after that memory has been deallocated or freed.\nIn this instance, the Sync component fails to correctly manage the lifecycle of objects during synchronization cycles. If a synchronization task holds a reference to an object, but a concurrent operation causes that object to be deallocated—without nullifying the reference—the dangling pointer remains active in memory. When the application subsequently attempts to perform operations on the freed memory, the resulting state is undefined and exploitable.\nThe attack flow begins when a remote attacker hosts a crafted HTML page containing JavaScript or web assembly primitives designed to trigger the specific state transition within the browser's Sync service. By manipulating the timing of DOM events or Sync background processes, the attacker influences the heap layout.\nOnce the target object is freed, the attacker utilizes heap grooming techniques, such as spraying the heap with controlled data, to reallocate the freed memory block with malicious content. When the browser attempts to access the original pointer to execute a virtual function or access an object member, it inadvertently executes code or follows a pointer controlled by the attacker.\nBecause this vulnerability allows for memory corruption within the browser's execution context, it effectively breaks the sandbox boundary. In the context of iOS, where applications operate within highly restricted containers, an escape allows the attacker to move beyond the browser's process constraints, potentially gaining unauthorized access to sensitive device functions or user data.\nThe exploitation process is sensitive to the specific memory management implementation of the Chromium engine on iOS. Attackers must ensure precise heap synchronization to ensure the dangling pointer maps to their controlled payload. Failure to do so typically results in a memory access violation, leading to a crash of the browser process rather than code execution. However, stable exploit chains are feasible for sophisticated attackers who can identify reliable triggers for the UAF condition within the synchronization task scheduler.\nAffected versions are strictly limited to those preceding 152.0.7977.65. The vulnerability does not require prior authentication and can be triggered remotely over the network via standard web traffic protocols."
}