Tencent WeChat WXAM Decoder Out-Of-Bounds Write Remote Code Execution Vulnerability

December 7th, 2021
ZDI-21-1456 ZDI-CAN-13368

CVE ID

CVSS Score

8.8 AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected Vendors

Tencent

Affected Products

WeChat

Vulnerability Details

This vulnerability allows remote attackers to execute arbitrary code on affected installations of Tencent WeChat. 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 WXAM decoder. The issue results from the lack of proper validation of user-supplied data, which can result in a write past the end of an allocated buffer. An attacker can leverage this vulnerability to execute code in the context of the current process.

Additional Details

Fixed in version 8.0.10


Disclosure Timeline

  • 2021-03-10 - Vulnerability reported to vendor
  • 2021-12-07 - Coordinated public release of advisory
  • 2021-12-08 - Advisory Updated

Credit

Mickey Jin (@patch1t) of Trend Micro

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