Description

Use after free in ServiceWorker in Google Chrome prior to 152.0.7977.65 allowed a remote attacker to execute arbitrary code outside the sandbox via a crafted HTML page. (Chromium security severity: Medium)

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "9.6",
  "pubDate": "2026-08-25T21:17:51.080Z",
  "pubdate": "2026-08-25T21:17:51.080Z",
  "executiveSummary": "A critical Use-After-Free (UAF) vulnerability exists within the ServiceWorker implementation of Google Chrome, identified in versions prior to 152.0.7977.65. This memory safety flaw occurs due to improper management of object lifecycles within the browser's ServiceWorker infrastructure.\nThe vulnerability allows a remote, unauthenticated attacker to execute arbitrary code outside the restricted sandbox environment by leveraging a specifically crafted HTML page. Successful exploitation compromises the integrity, confidentiality, and availability of the host system.\nThe risk implication is severe, as it bypasses standard browser security boundaries (sandboxing). Attackers can achieve Remote Code Execution (RCE) without user interaction beyond navigating to a malicious web page. The primary exploitation requirement is the victim's interaction with the crafted content, which triggers the UAF condition within the browser's rendering or worker process memory management layer.",
  "technicalDetails": "The vulnerability resides within the ServiceWorker subsystem of the Chromium browser engine. Use-After-Free (UAF) occurs when the memory management logic fails to properly track or nullify references to a specific object before that object is deallocated by the heap allocator.\nThe root cause involves a race condition or an improper reference count associated with the ServiceWorker registration or execution context. In the affected versions, the browser continues to hold or attempt to access a pointer to a ServiceWorker-related object after the memory has been reclaimed or freed. This creates a dangling pointer scenario where the freed memory may be reallocated for a different purpose while the ServiceWorker process still holds a stale reference.\nThe attack flow begins when a user navigates to an attacker-controlled HTML page. The page contains malicious scripts designed to manipulate the browser's memory heap, specifically targeting the ServiceWorker lifecycle events. By orchestrating a sequence of events—such as rapid registration, termination, and re-instantiation of ServiceWorkers—the attacker forces the browser to trigger a dangling pointer reference.\nOnce the UAF condition is achieved, the attacker utilizes heap grooming techniques to place controlled data in the memory location previously occupied by the freed object. When the browser accesses this now-controlled memory location through the stale pointer, it executes attacker-supplied instructions or redirects the control flow to an arbitrary memory address.\nBecause ServiceWorkers operate in an independent context with elevated privileges relative to standard web content, the ability to control execution via UAF enables the attacker to escape the Chromium sandbox. This bypasses the typical security architecture that prevents web content from modifying the underlying operating system. The post-exploitation impact includes the potential for arbitrary code execution with the permissions of the browser process, facilitating data exfiltration, installation of persistent malware, or further lateral movement within the user's environment. This vulnerability demonstrates a critical failure in the synchronization mechanisms governing the lifecycle of ServiceWorker threads and their associated IPC (Inter-Process Communication) messages."
}