Presumably each of these applications has asked you for the password. If not then that would be a security concern.
The password is stored in the file in an encrypted form. The method of converting the plain text to the encrypted (or hashed) form is known and implemented in each of the applications. They then compare the encrypted strings and if they match let you open the file.
It should be very difficult, if not impossible, to take the encrpyted string and convert it back into the plain text password - so there is no security risk.