The JsonParser class in json/JsonParser.scala in Lift before 2.5 interprets a certain end-index value as a length value, which allows remote authenticated users to obtain sensitive information from other users' sessions via invalid input data containing a < (less than) character.
The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.