TippingPoint Zero Day Initiative

Webkit fontface Invalid Font Family Remote Code Execution Vulnerability

ZDI-12-054: March 26th, 2012


CVSS Score

Affected Vendors

Affected Products


Vulnerability Details

This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Webkit. 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 parsing and utilization of font objects. When the code parses the @font-face CSS element it does not validate that the font-family is legitimate. Later, if the same font-family is applied within CSS the code will access an invalid element of its internal font object. This can be leveraged by a remote attacker to execute code under the context of the user running the browser.

Vendor Response

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

Disclosure Timeline

    2011-07-06 - Vulnerability reported to vendor
    2012-03-26 - Coordinated public release of advisory


This vulnerability was discovered by:
    wushi of team509