CVE-2021-28667: StackStorm st2 Infinite Loop Condition

The vulnerability stems from StackStorm's custom logging handler for stderr data. The advisory and blog post describe a scenario where byte string decoding in logging enters an infinite loop under specific locale conditions. The _handle_stderr_line function is explicitly mentioned in StackStorm's post-mortem as the location where decoding logic was modified to strip non-ASCII characters, confirming its role in the vulnerability. The file path is inferred from standard StackStorm logging configuration patterns and the nature of the fix described.