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Security Services

Apple Safari RenderBox Memory Corruption Vulnerability



Safari is Apple's web browser, and is based on the open source WebKit browser engine. For more information about Safari, please the visit following website:


Remote exploitation of a memory corruption vulnerability in Apple Inc.'s Safari browser could allow an attacker to execute arbitrary code with the privileges of the current user.

This vulnerability occurs when handling elements that have been appended to multiple parent elements. Specifically, Safari fails to properly remove a stale reference to a rendering object. When this occurs, the object is eventually freed twice. This results in uninitialized heap memory being treated as an object pointer, which can result in the execution of arbitrary code.


Exploitation of this vulnerability results in the execution of arbitrary code with the privileges of the user viewing the Web page. To exploit this vulnerability, a targeted user must load a malicious Web page created by an attacker. An attacker typically accomplishes this via social engineering or injecting content into compromised, trusted sites. After the user visits the malicious Web page, no further user interaction is needed.


The following Apple products are vulnerable:

  • Safari 5.0.5 and 5.0
  • iTunes 10.2.2

    iDefense is currently unaware of any workaround for this issue.


    Apple has released fixes which addresses this issue. Information about downloadable vendor updates can be found by clicking on the URLs shown.


    The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2011-0237 to this issue. This is a candidate for inclusion in the CVE list (, which standardizes names for security problems.


    06/01/2011 Initial Vendor Notification
    06/01/2011 Vendor Reply
    07/20/2011 Coordinated Public Disclosure


    This vulnerability was reported to iDefense by wushi of team509.

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    Copyright © 2011 Verisign, Inc.

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