diff --git a/spring-web/src/main/java/org/springframework/web/util/RfcUriParser.java b/spring-web/src/main/java/org/springframework/web/util/RfcUriParser.java
index c87c2a7b123..3198e93590a 100644
--- a/spring-web/src/main/java/org/springframework/web/util/RfcUriParser.java
+++ b/spring-web/src/main/java/org/springframework/web/util/RfcUriParser.java
@@ -241,12 +241,16 @@ abstract class RfcUriParser {
 						parser.index(++i);
 						parser.captureHost();
 						if (parser.hasNext()) {
-							if (parser.charAtIndex() == ':') {
+							char next = parser.charAtIndex();
+							if (next == ':') {
 								parser.advanceTo(PORT, i + 1);
 							}
-							else {
+							else if (next == '/') {
 								parser.advanceTo(PATH, i);
 							}
+							else {
+								fail(parser, "Bad authority");
+							}
 						}
 						break;
 					case ':':
diff --git a/spring-web/src/test/java/org/springframework/web/util/UriComponentsBuilderTests.java b/spring-web/src/test/java/org/springframework/web/util/UriComponentsBuilderTests.java
index e8729d97d9b..fc0a40a54c3 100644
--- a/spring-web/src/test/java/org/springframework/web/util/UriComponentsBuilderTests.java
+++ b/spring-web/src/test/java/org/springframework/web/util/UriComponentsBuilderTests.java
@@ -267,7 +267,10 @@ class UriComponentsBuilderTests {
 	@EnumSource
 	void fromUriStringInvalidIPv6Host(ParserType parserType) {
 		assertThatIllegalArgumentException().isThrownBy(() ->
-				UriComponentsBuilder.fromUriString("http://[1abc:2abc:3abc::5ABC:6abc:8080/resource", parserType));
+				UriComponentsBuilder.fromUriString("https://[1abc:2abc:3abc::5ABC:6abc:8080/resource", parserType));
+
+		assertThatIllegalArgumentException().isThrownBy(() ->
+				UriComponentsBuilder.fromUriString("https://[1abc:2abc:3abc::5ABC:6abc]resource", parserType));
 	}
 
 	@ParameterizedTest // gh-36759