A heap-based buffer overflow, leading to array index error was found in the way the Pango font rendering library rendered glyph box for certain FTBitmap objects, when the FreeType2 Pango back end was used for rendering. If an attacker created a specially-crafted font file and tricked a local, unsuspecting user into loading the font file in an application that uses the Pango font rendering library and FreeType2 Pango back end was used for rendering, it could cause that application to crash or, potentially, execute arbitrary code with the privileges of the user running the application.
References: [1] https://bugs.launchpad.net/ubuntu/+source/pango1.0/+bug/696616
CVE Request: [2] http://www.openwall.com/lists/oss-security/2011/01/18/6
Public PoC: [3] https://bugs.launchpad.net/ubuntu/+source/pango1.0/+bug/696616/comments/1 (malicious font) [4] https://bugs.launchpad.net/ubuntu/+source/pango1.0/+bug/696616/comments/2 (sample text file to trigger the crash)
Integer overflow in the pangoglyphstringsetsize function in pango/glyphstring.c in Pango before 1.24 allows context-dependent attackers to cause a denial of service (application crash) or possibly execute arbitrary code via a long glyph string that triggers a heap-based buffer overflow, as demonstrated by a long document.location value in Firefox.