TippingPoint Zero Day Initiative

Microsoft Chakra asm.js ArrayBuffer Use-After-Free Remote Code Execution Vulnerability

ZDI-17-848: October 11th, 2017


CVSS Score

Affected Vendors

Affected Products


Vulnerability Details

This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Microsoft Chakra. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.

The specific flaw exists within the handling of ArrayBuffer objects in asm.js. By performing actions in JavaScript an attacker can cause a pointer to be reused after it has been freed. An attacker can leverage this vulnerability to execute code under the context of the current process.

Vendor Response

Microsoft has issued an update to correct this vulnerability. More details can be found at:

Disclosure Timeline

    2017-09-01 - Vulnerability reported to vendor
    2017-10-11 - Coordinated public release of advisory


This vulnerability was discovered by:
    Simon Zuckerbraun - Trend Micro Zero Day Initiative