gh-109765: Detect TLS handshake attempt in HTTP server

Lib/http/server.py

@@ -287,6 +287,15 @@ def parse_request(self):
         requestline = str(self.raw_requestline, 'iso-8859-1')
         requestline = requestline.rstrip('\r\n')
         self.requestline = requestline
+
+        # Detect TLS handshake attempt (common when browser forces HTTPS)
+        if self.raw_requestline[0] == 0x16:  # First TLS handshake bytes
+            self.requestline = "[TLS handshake bytes]"
+            self.send_error(
+                HTTPStatus.BAD_REQUEST,
+                "Unsupported protocol: HTTPS is not available")
+            return False
+
         words = requestline.split()
         if len(words) == 0:
             return False

Misc/NEWS.d/next/Library/2025-02-12-18-31-12.gh-issue-109765.QqoBW2.rst

@@ -0,0 +1,2 @@
+Detect TLS handshake attempt in :class:`http.server.BaseHTTPRequestHandler` to
+more clear the output. Patch by Semyon Moroz.