C HTTP Parser Bypasses max_line_size for Fragmented Lines

Summary

It is possible to bypass the max_line_size check in parts of an HTTP request in the C parser.

Impact

If using the optimised C parser (the default in pre-built wheels), then an attacker may be able to send oversized lines through the HTTP parser and use an excessive amount of memory, potentially leading to DoS.

Patch: 5ab61bb