The pa_drop_root function in PulseAudio 0.9.8, and a certain 0.9.9 build, does not check return values from (1) setresuid, (2) setreuid, (3) setuid, and (4) seteuid calls when attempting to drop privileges, which might allow local users to gain privileges by causing those calls to fail via attacks such as resource exhaustion.
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.