Mozilla Firefox 3.0.8 and earlier 3.0.x versions allows remote attackers to cause a denial of service (memory corruption) via an XML document composed of a long series of start-tags with no corresponding end-tags. NOTE: it was later reported that 3.0.10 and earlier are also affected.
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.