414Request-URI Too Long

The server is refusing to service the request because the request-target¹ is longer than the server is willing to interpret.

This rare condition is only likely to occur when a client has improperly converted a POST request to a GET request with long query information, when the client has descended into a "black hole" of redirection (e.g., a redirected URI prefix that points to a suffix of itself) or when the server is under attack by a client attempting to exploit potential security holes.

A 414 response is cacheable by default; i.e., unless otherwise indicated by the method definition or explicit cache controls ².

• ¹ Content Negotiation RFC7230 Section 5.3
• ² Calculating Heuristic Freshness RFC7234 Section 4.2.2]3
• Source: RFC7231 Section 6.5.12