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Apple Safari innerText Use-After-Free Vulnerability



Safari is Apple's web browser, and is based on the open source WebKit browser engine. MobileSafari is Safari for Apple's mobile devices including the iPad and iPhone. For more information, see the vendor's site found at the following link.


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.

Safari is Apple's Web browser and is based on the open source WebKit browser engine.

This vulnerability occurs when Safari incorrectly handles an error state when encountering a broken XHTML tag. Specifically, the tag enclosing the tag being processed is freed and is then referenced after it has already been freed. This can lead to 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.


Safari versions prior to 5.1 and 5.0.6 are vulnerable.


Disabling JavaScript is an effective workaround for this vulnerability.


Apple Inc. has released patches which addresses this issue. For more information, consult their advisory at the following URL:


The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2011-0234 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 Initial 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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