TippingPoint Zero Day Initiative

Valve Steam User Chat Message Remote Code Execution Vulnerability

ZDI-13-269: November 24th, 2013

CVSS Score

Affected Vendors

Affected Products

Vulnerability Details

This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Valve Steam. No action is necessary on the part of the vulnerable Steam user other than signing on to the Steam service.

The specific flaw exists within the handling of user to user messages in the Steam client. An attacker can exploit this vulnerability by sending a malformed message to another Steam user via the Steam service. This can result in arbitrary code execution in the context of the Steam client.

Vendor Response

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

Disclosure Timeline

    2013-09-16 - Vulnerability reported to vendor
    2013-11-24 - Coordinated public release of advisory


This vulnerability was discovered by:
    Arnaud Dovi