Marc Schoenefeld discovered that Pango incorrectly handled certain Glyph Definition tables. If a user were tricked into displaying text with a specially-crafted font, an attacker could cause Pango to crash, resulting in a denial of service. This issue only affected Ubuntu 8.04 LTS and 9.10. Dan Rosenberg discovered that Pango incorrectly handled certain FT_Bitmap objects. If a user were tricked into displaying text with a specially- crafted font, an attacker could cause a denial of service or execute arbitrary code with privileges of the user invoking the program. The default compiler options for affected releases should reduce the vulnerability to a denial of service. It was discovered that Pango incorrectly handled certain memory reallocation failures. If a user were tricked into displaying text in a way that would cause a reallocation failure, an attacker could cause a denial of service or execute arbitrary code with privileges of the user invoking the program. This issue only affected Ubuntu 9.10, 10.04 LTS and 10.10