Parse pushed request URI from last delimiter

oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/server/authorization/authentication/OAuth2PushedAuthorizationRequestUri.java

@@ -59,7 +59,7 @@ static OAuth2PushedAuthorizationRequestUri create(Instant expiresAt) {
 
 	static OAuth2PushedAuthorizationRequestUri parse(String requestUri) {
 		int stateStartIndex = REQUEST_URI_PREFIX.length();
-		int expiresAtStartIndex = requestUri.indexOf(REQUEST_URI_DELIMITER) + REQUEST_URI_DELIMITER.length();
+		int expiresAtStartIndex = requestUri.lastIndexOf(REQUEST_URI_DELIMITER) + REQUEST_URI_DELIMITER.length();
 		OAuth2PushedAuthorizationRequestUri pushedAuthorizationRequestUri = new OAuth2PushedAuthorizationRequestUri();
 		pushedAuthorizationRequestUri.requestUri = requestUri;
 		pushedAuthorizationRequestUri.state = requestUri.substring(stateStartIndex);

oauth2-authorization-server/src/test/java/org/springframework/security/oauth2/server/authorization/authentication/OAuth2PushedAuthorizationRequestUriTests.java

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2026 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.security.oauth2.server.authorization.authentication;
+
+import java.time.Instant;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link OAuth2PushedAuthorizationRequestUri}.
+ *
+ * @author Goutam Adwant
+ */
+public class OAuth2PushedAuthorizationRequestUriTests {
+
+	@Test
+	public void parseWhenStateContainsDelimiterThenReturnRequestUri() {
+		Instant expiresAt = Instant.parse("2026-06-17T10:00:00Z");
+		String requestUri = "urn:ietf:params:oauth:request_uri:xXMGJTZwzXIFL8i_DFu_EM8IeWC___frCWjpiF2q-xs=___"
+				+ expiresAt.toEpochMilli();
+
+		OAuth2PushedAuthorizationRequestUri pushedAuthorizationRequestUri = OAuth2PushedAuthorizationRequestUri
+			.parse(requestUri);
+
+		assertThat(pushedAuthorizationRequestUri.getRequestUri()).isEqualTo(requestUri);
+		assertThat(pushedAuthorizationRequestUri.getState())
+			.isEqualTo("xXMGJTZwzXIFL8i_DFu_EM8IeWC___frCWjpiF2q-xs=___" + expiresAt.toEpochMilli());
+		assertThat(pushedAuthorizationRequestUri.getExpiresAt()).isEqualTo(expiresAt);
+	}
+
+}