diff --git a/build.gradle b/build.gradle
index a382050d4e..c3c41e4ca1 100644
--- a/build.gradle
+++ b/build.gradle
@@ -207,6 +207,7 @@ configure(allprojects) { project ->
 			}
 			dependency "org.skyscreamer:jsonassert:1.5.0"
 			dependency "com.jayway.jsonpath:json-path:2.4.0"
+			dependency "org.bouncycastle:bcpkix-jdk15on:1.65"
 
 			dependencySet(group: 'org.apache.tiles', version: '3.0.8') {
 				entry 'tiles-api'
diff --git a/spring-web/spring-web.gradle b/spring-web/spring-web.gradle
index 48599d427a..25e4a9092d 100644
--- a/spring-web/spring-web.gradle
+++ b/spring-web/spring-web.gradle
@@ -83,4 +83,7 @@ dependencies {
 	testFixturesImplementation("io.projectreactor:reactor-test")
 	testFixturesImplementation("org.apache.taglibs:taglibs-standard-jstlel")
 	testFixturesImplementation("org.assertj:assertj-core")
+	testFixturesImplementation("org.bouncycastle:bcpkix-jdk15on") {
+		because("needed by Netty's SelfSignedCertificate on JDK 15+")
+	}
 }