IBM Db2 for Linux, UNIX and Windows (includes DB2 Connect Server) 11.5.0 - 11.5.9 and 12.1.0 - 12.1.3 could allow an unauthenticated user to cause a denial of service due to excessive use of a global variable.
Weakness
The code is structured in a way that relies too much on using or setting global variables throughout various points in the code, instead of preserving the associated information in a narrower, more local context.