Integer overflow in camel-lock-helper in Evolution 2.0.2 and earlier allows local users or remote malicious POP3 servers to execute arbitrary code via a length value of -1, which leads to a zero byte memory allocation and a buffer overflow.
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.