ftp://ftp.software.ibm.com/common/ss...W14198USEN.PDF

e. Race conditions
Two processes might share control or data. Race conditions isthe term applied to compromising this sharing, which typicallyresults from synchronization errors, when the potential existsfor process conflicts, and a resulting vulnerability. A typicalexploit interrupts a pair of sequential calls that are meant to beperformed automatically without interruption by anotherthread or process on the machine with a third process.

One example is the combined checking of access rights to afile, followed by a subsequent call to write or read that file. Byinterrupting the process between the two calls, an attacker canrewrite or modify the file because this behavior is expected.The attacker can place inappropriate information into a file,or perhaps access an inappropriate file.
May someone explain more about that situation