The vulnerability specifically affects ScramServer's proof verification mechanism. Timing attacks require observable differences in processing time between valid and invalid inputs. The critical point would be in client proof validation where a standard string comparison (non-constant-time) was likely used. While no direct patch is shown, the CWE-203 classification and SCRAM protocol context indicate proof comparison functions as the vulnerable area. The main vulnerable function would be the direct proof validator(), with the authentication handler being a secondary indicator.