When processing subtitles format media file, KMPlayer version 2018.12.24.14 or lower doesn't check object size correctly, which leads to integer underflow then to memory out-of-bound read/write. An attacker can exploit this issue by enticing an unsuspecting user to open a malicious file.
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.
The product subtracts one value from another, such that the result is less than the minimum allowable integer value, which produces a value that is not equal to the correct result.