Description

Use after free in Microsoft Edge (Chromium-based) allows an unauthorized attacker to execute code over a network.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "4.3",
  "pubDate": "2026-08-28T20:19:34.673Z",
  "pubdate": "2026-08-28T20:19:34.673Z",
  "executiveSummary": "A critical use-after-free (UAF) vulnerability exists within the Chromium-based architecture of the Microsoft Edge browser.\nThis memory corruption flaw allows a remote, unauthorized attacker to execute arbitrary code on the host system via network-based vectors.\nThe vulnerability stems from improper memory management within the browser engine, specifically during the handling of object lifecycles.\nSuccessful exploitation poses a significant security risk, as it allows attackers to bypass browser sandboxing mechanisms, potentially leading to full system compromise.\nThere are no specific authentication or local access requirements for an attacker to initiate the exploit, as it can be triggered through a malicious network request or interaction with compromised web content.\nThe primary risk involves remote code execution (RCE), which could lead to data exfiltration, malware installation, or persistent system infiltration.\nUsers and administrators are advised to prioritize the application of vendor-provided security updates to mitigate this memory-related threat.",
  "technicalDetails": "The vulnerability is characterized as a use-after-free (UAF) memory corruption flaw occurring within the Chromium-based rendering engine used by Microsoft Edge.\nA use-after-free condition arises when an application continues to use a pointer to a memory location after that memory has been deallocated or freed.\nIn the context of the browser, this often involves the manipulation of Document Object Model (DOM) elements or underlying C++ objects during asynchronous operations or garbage collection cycles.\nThe root cause typically involves a race condition or an incorrect reference counting mechanism where an object remains reachable by the execution flow even after the underlying memory has been returned to the allocator.\nAn attacker can exploit this by triggering specific sequences of JavaScript or network interactions that force the browser to reclaim memory while a dangling pointer remains active in a separate thread or process execution.\nThe exploitation flow generally follows these phases: 1) Heap Spraying: The attacker populates the heap with controlled data to increase the predictability of memory layout. 2) Triggering the UAF: The attacker forces the browser to free an object while retaining a reference to it in the engine. 3) Memory Reallocation: The attacker initiates a new allocation of the same size, aiming to occupy the exact memory address previously held by the freed object. 4) Exploitation: The attacker overwrites the data at the dangling pointer location with malicious instructions or fake object structures (e.g., vtable pointers).\nOnce the attacker successfully redirects the execution flow, they can pivot from the initial memory corruption to arbitrary code execution, often bypassing modern exploit mitigations like Address Space Layout Randomization (ASLR) and Data Execution Prevention (DEP).\nBecause the vulnerability exists in the Chromium core, the attack surface is exposed via any network-based interaction where the browser processes untrusted content. This includes navigating to malicious websites or interacting with embedded advertisements designed to exploit browser memory handlers. Post-exploitation, the attacker operates with the privileges of the browser process, which can then be escalated if secondary vulnerabilities in the kernel or host operating system are leveraged."
}