diff --git a/crypto/spring-security-crypto.gradle b/crypto/spring-security-crypto.gradle
index 0894300dbc..55aa092b80 100644
--- a/crypto/spring-security-crypto.gradle
+++ b/crypto/spring-security-crypto.gradle
@@ -4,7 +4,7 @@ dependencies {
 	management platform(project(":spring-security-dependencies"))
 	optional 'org.springframework:spring-jcl'
 	optional 'org.springframework:spring-core'
-	optional 'org.bouncycastle:bcpkix-jdk15on'
+	optional 'org.bouncycastle:bcpkix-jdk18on'
 
 	testImplementation "org.assertj:assertj-core"
 	testImplementation "org.junit.jupiter:junit-jupiter-api"
diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
index b05972e438..e5bde60293 100644
--- a/gradle/libs.versions.toml
+++ b/gradle/libs.versions.toml
@@ -7,7 +7,7 @@ jakarta-websocket = "2.1.1"
 org-apache-directory-server = "1.5.5"
 org-apache-maven-resolver = "1.9.18"
 org-aspectj = "1.9.22"
-org-bouncycastle = "1.70"
+org-bouncycastle = "1.78"
 org-eclipse-jetty = "11.0.20"
 org-jetbrains-kotlin = "1.9.23"
 org-jetbrains-kotlinx = "1.8.0"
@@ -62,8 +62,8 @@ io-freefair-gradle-aspectj-plugin = "io.freefair.gradle:aspectj-plugin:8.6"
 org-aspectj-aspectjrt = { module = "org.aspectj:aspectjrt", version.ref = "org-aspectj" }
 org-aspectj-aspectjweaver = { module = "org.aspectj:aspectjweaver", version.ref = "org-aspectj" }
 org-assertj-assertj-core = "org.assertj:assertj-core:3.25.3"
-org-bouncycastle-bcpkix-jdk15on = { module = "org.bouncycastle:bcpkix-jdk15on", version.ref = "org-bouncycastle" }
-org-bouncycastle-bcprov-jdk15on = { module = "org.bouncycastle:bcprov-jdk15on", version.ref = "org-bouncycastle" }
+org-bouncycastle-bcpkix-jdk15on = { module = "org.bouncycastle:bcpkix-jdk18on", version.ref = "org-bouncycastle" }
+org-bouncycastle-bcprov-jdk15on = { module = "org.bouncycastle:bcprov-jdk18on", version.ref = "org-bouncycastle" }
 org-eclipse-jetty-jetty-server = { module = "org.eclipse.jetty:jetty-server", version.ref = "org-eclipse-jetty" }
 org-eclipse-jetty-jetty-servlet = { module = "org.eclipse.jetty:jetty-servlet", version.ref = "org-eclipse-jetty" }
 org-hamcrest = "org.hamcrest:hamcrest:2.2"
diff --git a/oauth2/oauth2-jose/spring-security-oauth2-jose.gradle b/oauth2/oauth2-jose/spring-security-oauth2-jose.gradle
index c5b4b113df..3f449f18e6 100644
--- a/oauth2/oauth2-jose/spring-security-oauth2-jose.gradle
+++ b/oauth2/oauth2-jose/spring-security-oauth2-jose.gradle
@@ -10,8 +10,8 @@ dependencies {
 	optional 'io.projectreactor:reactor-core'
 	optional 'org.springframework:spring-webflux'
 
-	testImplementation "org.bouncycastle:bcpkix-jdk15on"
-	testImplementation "org.bouncycastle:bcprov-jdk15on"
+	testImplementation "org.bouncycastle:bcpkix-jdk18on"
+	testImplementation "org.bouncycastle:bcprov-jdk18on"
 	testImplementation "jakarta.servlet:jakarta.servlet-api"
 	testImplementation 'com.squareup.okhttp3:mockwebserver'
 	testImplementation 'io.projectreactor.netty:reactor-netty'