Public Vulnerability Reports

Adobe Reader Embedded Font Handling Out of Bounds Array Indexing Vulnerability



Adobe Acrobat Reader is a program for viewing Portable Document Format (PDF) documents. More information is available at the following site:


Remote exploitation of an out of bounds array access vulnerability in Adobe System Inc.'s Adobe Reader could allow an attacker to execute arbitrary code as the current user.

The vulnerability specifically exists in code responsible for parsing Type 1 fonts. After allocating an area of memory, no bounds checking is performed. Subsequent access of this memory may result in modification of arbitrary memory, which in turn may result in arbitrary code execution.


Exploitation of this vulnerability would allow a remote attacker to execute arbitrary code as the current user. In order to exploit this vulnerability, the attacker would have to convince the target user to open a maliciously crafted file, either by opening an email attachment or visiting a website which contained an embedded PDF file. No further interaction is required. The Explorer extension which displays the thumbnail view of the document, AcroRd32Info, is also vulnerable. This may allow the vulnerability to be exploited by simply clicking on a PDF file without opening it, even from a network share.


iDefense has confirmed the existence of this vulnerability in Adobe Reader version 8.1.1. Previous versions may also be affected.


iDefense is currently unaware of any effective workarounds for this issue.

Configuring the application not to open in the browser may mitigate exposure to some web-based attacks.


Adobe has released a patch 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-2008-4812 to this issue. This is a candidate for inclusion in the CVE list (, which standardizes names for security problems.


12/27/2007 Initial Vendor Notification
12/28/2007 Initial Vendor Reply
10/31/2008 Additional Vendor Feedback
11/04/2008 Coordinated Public Disclosure


This vulnerability was discovered by to Greg MacManus of iDefense Labs.

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Copyright © 2008 Verisign, Inc.

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