SQLite before 3.25.3, when the FTS3 extension is enabled, encounters an integer overflow (and resultant buffer overflow) for FTS3 queries that occur after crafted changes to FTS3 shadow tables, allowing remote attackers to execute arbitrary code by leveraging the ability to run arbitrary SQL statements (such as in certain WebSQL use cases), aka Magellan.
The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.