Return 415 rather than 400 on Urlencoded Content-Type mismatch

actix-web/CHANGES.md

@@ -10,6 +10,8 @@
 
 - Minimum supported Rust version (MSRV) is now 1.72.
 
+- the Urlencoded extractor now returns 415 (Media Type Unsupported) if the request's `Content-Type` is not `application/x-www-form-urlencoded`, rather than 400 (Bad Request).
+
 ## 4.5.1
 
 ### Fixed

actix-web/src/error/mod.rs

@@ -100,6 +100,7 @@ impl ResponseError for UrlencodedError {
         match self {
             Self::Overflow { .. } => StatusCode::PAYLOAD_TOO_LARGE,
             Self::UnknownLength => StatusCode::LENGTH_REQUIRED,
+            Self::ContentType => StatusCode::UNSUPPORTED_MEDIA_TYPE,
             Self::Payload(err) => err.status_code(),
             _ => StatusCode::BAD_REQUEST,
         }