diff --git a/config/src/test/java/org/springframework/security/SpringSecurityCoreVersionSerializableTests.java b/config/src/test/java/org/springframework/security/SpringSecurityCoreVersionSerializableTests.java
index 2b037d1e1a..1f6f2da423 100644
--- a/config/src/test/java/org/springframework/security/SpringSecurityCoreVersionSerializableTests.java
+++ b/config/src/test/java/org/springframework/security/SpringSecurityCoreVersionSerializableTests.java
@@ -196,6 +196,18 @@
 import org.springframework.security.web.firewall.RequestRejectedException;
 import org.springframework.security.web.server.firewall.ServerExchangeRejectedException;
 import org.springframework.security.web.session.HttpSessionCreatedEvent;
+import org.springframework.security.web.webauthn.api.AuthenticationExtensionsClientInputs;
+import org.springframework.security.web.webauthn.api.AuthenticatorTransport;
+import org.springframework.security.web.webauthn.api.Bytes;
+import org.springframework.security.web.webauthn.api.CredProtectAuthenticationExtensionsClientInput;
+import org.springframework.security.web.webauthn.api.ImmutableAuthenticationExtensionsClientInput;
+import org.springframework.security.web.webauthn.api.ImmutableAuthenticationExtensionsClientInputs;
+import org.springframework.security.web.webauthn.api.PublicKeyCredentialDescriptor;
+import org.springframework.security.web.webauthn.api.PublicKeyCredentialRequestOptions;
+import org.springframework.security.web.webauthn.api.PublicKeyCredentialType;
+import org.springframework.security.web.webauthn.api.TestBytes;
+import org.springframework.security.web.webauthn.api.TestPublicKeyCredentialRequestOptions;
+import org.springframework.security.web.webauthn.api.UserVerificationRequirement;
 import org.springframework.util.ReflectionUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
@@ -515,6 +527,39 @@ class SpringSecurityCoreVersionSerializableTests {
 				(r) -> new AuthenticationSwitchUserEvent(authentication, user));
 		generatorByClassName.put(HttpSessionCreatedEvent.class,
 				(r) -> new HttpSessionCreatedEvent(new MockHttpSession()));
+
+		// webauthn
+		CredProtectAuthenticationExtensionsClientInput.CredProtect credProtect = new CredProtectAuthenticationExtensionsClientInput.CredProtect(
+				CredProtectAuthenticationExtensionsClientInput.CredProtect.ProtectionPolicy.USER_VERIFICATION_OPTIONAL,
+				true);
+		Bytes id = TestBytes.get();
+		AuthenticationExtensionsClientInputs inputs = new ImmutableAuthenticationExtensionsClientInputs(
+				ImmutableAuthenticationExtensionsClientInput.credProps);
+		// @formatter:off
+		PublicKeyCredentialDescriptor descriptor = PublicKeyCredentialDescriptor.builder()
+				.id(id)
+				.type(PublicKeyCredentialType.PUBLIC_KEY)
+				.transports(Set.of(AuthenticatorTransport.USB))
+				.build();
+		// @formatter:on
+		generatorByClassName.put(AuthenticatorTransport.class, (a) -> AuthenticatorTransport.USB);
+		generatorByClassName.put(PublicKeyCredentialType.class, (k) -> PublicKeyCredentialType.PUBLIC_KEY);
+		generatorByClassName.put(UserVerificationRequirement.class, (r) -> UserVerificationRequirement.REQUIRED);
+		generatorByClassName.put(CredProtectAuthenticationExtensionsClientInput.CredProtect.class, (c) -> credProtect);
+		generatorByClassName.put(CredProtectAuthenticationExtensionsClientInput.class,
+				(c) -> new CredProtectAuthenticationExtensionsClientInput(credProtect));
+		generatorByClassName.put(ImmutableAuthenticationExtensionsClientInputs.class, (i) -> inputs);
+		generatorByClassName.put(ImmutableAuthenticationExtensionsClientInput.class,
+				(i) -> ImmutableAuthenticationExtensionsClientInput.credProps);
+		generatorByClassName.put(Bytes.class, (b) -> id);
+		generatorByClassName.put(PublicKeyCredentialDescriptor.class, (d) -> descriptor);
+		// @formatter:off
+		generatorByClassName.put(PublicKeyCredentialRequestOptions.class, (o) -> TestPublicKeyCredentialRequestOptions.create()
+				.extensions(inputs)
+				.allowCredentials(List.of(descriptor))
+				.build()
+		);
+		// @formatter:on
 	}
 
 	@ParameterizedTest
diff --git a/config/src/test/resources/serialized/6.5.x/org.springframework.security.web.webauthn.api.AuthenticatorTransport.serialized b/config/src/test/resources/serialized/6.5.x/org.springframework.security.web.webauthn.api.AuthenticatorTransport.serialized
new file mode 100644
index 0000000000..183124aa4e
Binary files /dev/null and b/config/src/test/resources/serialized/6.5.x/org.springframework.security.web.webauthn.api.AuthenticatorTransport.serialized differ
diff --git a/config/src/test/resources/serialized/6.5.x/org.springframework.security.web.webauthn.api.Bytes.serialized b/config/src/test/resources/serialized/6.5.x/org.springframework.security.web.webauthn.api.Bytes.serialized
new file mode 100644
index 0000000000..e45bced432
Binary files /dev/null and b/config/src/test/resources/serialized/6.5.x/org.springframework.security.web.webauthn.api.Bytes.serialized differ
diff --git a/config/src/test/resources/serialized/6.5.x/org.springframework.security.web.webauthn.api.CredProtectAuthenticationExtensionsClientInput$CredProtect.serialized b/config/src/test/resources/serialized/6.5.x/org.springframework.security.web.webauthn.api.CredProtectAuthenticationExtensionsClientInput$CredProtect.serialized
new file mode 100644
index 0000000000..0222d302d6
Binary files /dev/null and b/config/src/test/resources/serialized/6.5.x/org.springframework.security.web.webauthn.api.CredProtectAuthenticationExtensionsClientInput$CredProtect.serialized differ
diff --git a/config/src/test/resources/serialized/6.5.x/org.springframework.security.web.webauthn.api.CredProtectAuthenticationExtensionsClientInput.serialized b/config/src/test/resources/serialized/6.5.x/org.springframework.security.web.webauthn.api.CredProtectAuthenticationExtensionsClientInput.serialized
new file mode 100644
index 0000000000..0b0b44e588
Binary files /dev/null and b/config/src/test/resources/serialized/6.5.x/org.springframework.security.web.webauthn.api.CredProtectAuthenticationExtensionsClientInput.serialized differ
diff --git a/config/src/test/resources/serialized/6.5.x/org.springframework.security.web.webauthn.api.ImmutableAuthenticationExtensionsClientInput.serialized b/config/src/test/resources/serialized/6.5.x/org.springframework.security.web.webauthn.api.ImmutableAuthenticationExtensionsClientInput.serialized
new file mode 100644
index 0000000000..604e609fca
Binary files /dev/null and b/config/src/test/resources/serialized/6.5.x/org.springframework.security.web.webauthn.api.ImmutableAuthenticationExtensionsClientInput.serialized differ
diff --git a/config/src/test/resources/serialized/6.5.x/org.springframework.security.web.webauthn.api.ImmutableAuthenticationExtensionsClientInputs.serialized b/config/src/test/resources/serialized/6.5.x/org.springframework.security.web.webauthn.api.ImmutableAuthenticationExtensionsClientInputs.serialized
new file mode 100644
index 0000000000..d5b3e16ebf
Binary files /dev/null and b/config/src/test/resources/serialized/6.5.x/org.springframework.security.web.webauthn.api.ImmutableAuthenticationExtensionsClientInputs.serialized differ
diff --git a/config/src/test/resources/serialized/6.5.x/org.springframework.security.web.webauthn.api.PublicKeyCredentialDescriptor.serialized b/config/src/test/resources/serialized/6.5.x/org.springframework.security.web.webauthn.api.PublicKeyCredentialDescriptor.serialized
new file mode 100644
index 0000000000..7de3d58f80
Binary files /dev/null and b/config/src/test/resources/serialized/6.5.x/org.springframework.security.web.webauthn.api.PublicKeyCredentialDescriptor.serialized differ
diff --git a/config/src/test/resources/serialized/6.5.x/org.springframework.security.web.webauthn.api.PublicKeyCredentialRequestOptions.serialized b/config/src/test/resources/serialized/6.5.x/org.springframework.security.web.webauthn.api.PublicKeyCredentialRequestOptions.serialized
new file mode 100644
index 0000000000..399fa41229
Binary files /dev/null and b/config/src/test/resources/serialized/6.5.x/org.springframework.security.web.webauthn.api.PublicKeyCredentialRequestOptions.serialized differ
diff --git a/config/src/test/resources/serialized/6.5.x/org.springframework.security.web.webauthn.api.PublicKeyCredentialType.serialized b/config/src/test/resources/serialized/6.5.x/org.springframework.security.web.webauthn.api.PublicKeyCredentialType.serialized
new file mode 100644
index 0000000000..efc9d8e3ee
Binary files /dev/null and b/config/src/test/resources/serialized/6.5.x/org.springframework.security.web.webauthn.api.PublicKeyCredentialType.serialized differ
diff --git a/config/src/test/resources/serialized/6.5.x/org.springframework.security.web.webauthn.api.UserVerificationRequirement.serialized b/config/src/test/resources/serialized/6.5.x/org.springframework.security.web.webauthn.api.UserVerificationRequirement.serialized
new file mode 100644
index 0000000000..7fde55c0e1
Binary files /dev/null and b/config/src/test/resources/serialized/6.5.x/org.springframework.security.web.webauthn.api.UserVerificationRequirement.serialized differ
diff --git a/web/src/main/java/org/springframework/security/web/webauthn/api/AuthenticationExtensionsClientInput.java b/web/src/main/java/org/springframework/security/web/webauthn/api/AuthenticationExtensionsClientInput.java
index f3fb229af1..736a3b2960 100644
--- a/web/src/main/java/org/springframework/security/web/webauthn/api/AuthenticationExtensionsClientInput.java
+++ b/web/src/main/java/org/springframework/security/web/webauthn/api/AuthenticationExtensionsClientInput.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2024 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -16,6 +16,8 @@
 
 package org.springframework.security.web.webauthn.api;
 
+import java.io.Serializable;
+
 /**
  * A client extension
  * input entry in the {@link AuthenticationExtensionsClientInputs}.
@@ -25,7 +27,7 @@
  * @since 6.4
  * @see ImmutableAuthenticationExtensionsClientInput
  */
-public interface AuthenticationExtensionsClientInput {
+public interface AuthenticationExtensionsClientInput extends Serializable {
 
 	/**
 	 * Gets the extension
diff --git a/web/src/main/java/org/springframework/security/web/webauthn/api/AuthenticationExtensionsClientInputs.java b/web/src/main/java/org/springframework/security/web/webauthn/api/AuthenticationExtensionsClientInputs.java
index 44a26a41c1..3befaa601f 100644
--- a/web/src/main/java/org/springframework/security/web/webauthn/api/AuthenticationExtensionsClientInputs.java
+++ b/web/src/main/java/org/springframework/security/web/webauthn/api/AuthenticationExtensionsClientInputs.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2024 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -16,6 +16,7 @@
 
 package org.springframework.security.web.webauthn.api;
 
+import java.io.Serializable;
 import java.util.List;
 
 /**
@@ -31,7 +32,7 @@
  * @since 6.4
  * @see PublicKeyCredentialCreationOptions#getExtensions()
  */
-public interface AuthenticationExtensionsClientInputs {
+public interface AuthenticationExtensionsClientInputs extends Serializable {
 
 	/**
 	 * Gets all of the {@link AuthenticationExtensionsClientInput}.
diff --git a/web/src/main/java/org/springframework/security/web/webauthn/api/AuthenticatorTransport.java b/web/src/main/java/org/springframework/security/web/webauthn/api/AuthenticatorTransport.java
index 33e9d2123c..0974d29569 100644
--- a/web/src/main/java/org/springframework/security/web/webauthn/api/AuthenticatorTransport.java
+++ b/web/src/main/java/org/springframework/security/web/webauthn/api/AuthenticatorTransport.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2024 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -16,6 +16,9 @@
 
 package org.springframework.security.web.webauthn.api;
 
+import java.io.Serial;
+import java.io.Serializable;
+
 /**
  * AuthenticatorTransport
@@ -25,7 +28,10 @@
  * @author Rob Winch
  * @since 6.4
  */
-public final class AuthenticatorTransport {
+public final class AuthenticatorTransport implements Serializable {
+
+	@Serial
+	private static final long serialVersionUID = -5617945441117386982L;
 
 	/**
 	 * usbc
diff --git a/web/src/main/java/org/springframework/security/web/webauthn/api/Bytes.java b/web/src/main/java/org/springframework/security/web/webauthn/api/Bytes.java
index 6fbcc3596c..7a2c769ad4 100644
--- a/web/src/main/java/org/springframework/security/web/webauthn/api/Bytes.java
+++ b/web/src/main/java/org/springframework/security/web/webauthn/api/Bytes.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2024 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -16,6 +16,8 @@
 
 package org.springframework.security.web.webauthn.api;
 
+import java.io.Serial;
+import java.io.Serializable;
 import java.security.SecureRandom;
 import java.util.Arrays;
 import java.util.Base64;
@@ -28,7 +30,10 @@
  * @author Rob Winch
  * @since 6.4
  */
-public final class Bytes {
+public final class Bytes implements Serializable {
+
+	@Serial
+	private static final long serialVersionUID = -7420539646106189663L;
 
 	private static final SecureRandom RANDOM = new SecureRandom();
 
diff --git a/web/src/main/java/org/springframework/security/web/webauthn/api/CredProtectAuthenticationExtensionsClientInput.java b/web/src/main/java/org/springframework/security/web/webauthn/api/CredProtectAuthenticationExtensionsClientInput.java
index 2237271759..e28da6d789 100644
--- a/web/src/main/java/org/springframework/security/web/webauthn/api/CredProtectAuthenticationExtensionsClientInput.java
+++ b/web/src/main/java/org/springframework/security/web/webauthn/api/CredProtectAuthenticationExtensionsClientInput.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2024 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -16,6 +16,9 @@
 
 package org.springframework.security.web.webauthn.api;
 
+import java.io.Serial;
+import java.io.Serializable;
+
 /**
  * Implements 
@@ -27,6 +30,9 @@
 public class CredProtectAuthenticationExtensionsClientInput
 		implements AuthenticationExtensionsClientInput {
 
+	@Serial
+	private static final long serialVersionUID = -6418175591005843455L;
+
 	private final CredProtect input;
 
 	public CredProtectAuthenticationExtensionsClientInput(CredProtect input) {
@@ -43,7 +49,10 @@ public CredProtect getInput() {
 		return this.input;
 	}
 
-	public static class CredProtect {
+	public static class CredProtect implements Serializable {
+
+		@Serial
+		private static final long serialVersionUID = 109597301115842688L;
 
 		private final ProtectionPolicy credProtectionPolicy;
 
diff --git a/web/src/main/java/org/springframework/security/web/webauthn/api/ImmutableAuthenticationExtensionsClientInput.java b/web/src/main/java/org/springframework/security/web/webauthn/api/ImmutableAuthenticationExtensionsClientInput.java
index eb656c3cdf..ad479b4a01 100644
--- a/web/src/main/java/org/springframework/security/web/webauthn/api/ImmutableAuthenticationExtensionsClientInput.java
+++ b/web/src/main/java/org/springframework/security/web/webauthn/api/ImmutableAuthenticationExtensionsClientInput.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2024 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -16,6 +16,8 @@
 
 package org.springframework.security.web.webauthn.api;
 
+import java.io.Serial;
+
 /**
  * An immutable {@link AuthenticationExtensionsClientInput}.
  *
@@ -26,6 +28,9 @@
  */
 public class ImmutableAuthenticationExtensionsClientInput implements AuthenticationExtensionsClientInput {
 
+	@Serial
+	private static final long serialVersionUID = -1738152485672656808L;
+
 	/**
 	 * https://www.w3.org/TR/webauthn-3/#sctn-authenticator-credential-properties-extension
 	 */
diff --git a/web/src/main/java/org/springframework/security/web/webauthn/api/ImmutableAuthenticationExtensionsClientInputs.java b/web/src/main/java/org/springframework/security/web/webauthn/api/ImmutableAuthenticationExtensionsClientInputs.java
index cef29f378a..f9c43608b1 100644
--- a/web/src/main/java/org/springframework/security/web/webauthn/api/ImmutableAuthenticationExtensionsClientInputs.java
+++ b/web/src/main/java/org/springframework/security/web/webauthn/api/ImmutableAuthenticationExtensionsClientInputs.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2024 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -16,6 +16,7 @@
 
 package org.springframework.security.web.webauthn.api;
 
+import java.io.Serial;
 import java.util.Arrays;
 import java.util.List;
 
@@ -27,6 +28,9 @@
  */
 public class ImmutableAuthenticationExtensionsClientInputs implements AuthenticationExtensionsClientInputs {
 
+	@Serial
+	private static final long serialVersionUID = 4277817521578485720L;
+
 	private final List inputs;
 
 	public ImmutableAuthenticationExtensionsClientInputs(List inputs) {
diff --git a/web/src/main/java/org/springframework/security/web/webauthn/api/PublicKeyCredentialDescriptor.java b/web/src/main/java/org/springframework/security/web/webauthn/api/PublicKeyCredentialDescriptor.java
index ad454814b0..6fbe5250ac 100644
--- a/web/src/main/java/org/springframework/security/web/webauthn/api/PublicKeyCredentialDescriptor.java
+++ b/web/src/main/java/org/springframework/security/web/webauthn/api/PublicKeyCredentialDescriptor.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2024 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -16,6 +16,8 @@
 
 package org.springframework.security.web.webauthn.api;
 
+import java.io.Serial;
+import java.io.Serializable;
 import java.util.Set;
 
 /**
@@ -29,7 +31,10 @@
  * @author Rob Winch
  * @since 6.4
  */
-public final class PublicKeyCredentialDescriptor {
+public final class PublicKeyCredentialDescriptor implements Serializable {
+
+	@Serial
+	private static final long serialVersionUID = 8793385059692676240L;
 
 	private final PublicKeyCredentialType type;
 
diff --git a/web/src/main/java/org/springframework/security/web/webauthn/api/PublicKeyCredentialRequestOptions.java b/web/src/main/java/org/springframework/security/web/webauthn/api/PublicKeyCredentialRequestOptions.java
index b0cf592009..9cadc1cb29 100644
--- a/web/src/main/java/org/springframework/security/web/webauthn/api/PublicKeyCredentialRequestOptions.java
+++ b/web/src/main/java/org/springframework/security/web/webauthn/api/PublicKeyCredentialRequestOptions.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2024 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -16,6 +16,8 @@
 
 package org.springframework.security.web.webauthn.api;
 
+import java.io.Serial;
+import java.io.Serializable;
 import java.time.Duration;
 import java.util.ArrayList;
 import java.util.Collections;
@@ -32,7 +34,10 @@
  * @author Rob Winch
  * @since 6.4
  */
-public final class PublicKeyCredentialRequestOptions {
+public final class PublicKeyCredentialRequestOptions implements Serializable {
+
+	@Serial
+	private static final long serialVersionUID = -2970057592835694354L;
 
 	private final Bytes challenge;
 
diff --git a/web/src/main/java/org/springframework/security/web/webauthn/api/PublicKeyCredentialType.java b/web/src/main/java/org/springframework/security/web/webauthn/api/PublicKeyCredentialType.java
index 57f1c6ec46..99087a5d29 100644
--- a/web/src/main/java/org/springframework/security/web/webauthn/api/PublicKeyCredentialType.java
+++ b/web/src/main/java/org/springframework/security/web/webauthn/api/PublicKeyCredentialType.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2024 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -16,6 +16,9 @@
 
 package org.springframework.security.web.webauthn.api;
 
+import java.io.Serial;
+import java.io.Serializable;
+
 /**
  * The PublicKeyCredentialType
@@ -24,7 +27,10 @@
  * @author Rob Winch
  * @since 6.4
  */
-public final class PublicKeyCredentialType {
+public final class PublicKeyCredentialType implements Serializable {
+
+	@Serial
+	private static final long serialVersionUID = 7025333122210061679L;
 
 	/**
 	 * The only credential type that currently exists.
diff --git a/web/src/main/java/org/springframework/security/web/webauthn/api/UserVerificationRequirement.java b/web/src/main/java/org/springframework/security/web/webauthn/api/UserVerificationRequirement.java
index adc915015b..dcbabead87 100644
--- a/web/src/main/java/org/springframework/security/web/webauthn/api/UserVerificationRequirement.java
+++ b/web/src/main/java/org/springframework/security/web/webauthn/api/UserVerificationRequirement.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2024 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -16,6 +16,9 @@
 
 package org.springframework.security.web.webauthn.api;
 
+import java.io.Serial;
+import java.io.Serializable;
+
 /**
  * UserVerificationRequirement
@@ -24,7 +27,10 @@
  * @author Rob Winch
  * @since 6.4
  */
-public final class UserVerificationRequirement {
+public final class UserVerificationRequirement implements Serializable {
+
+	@Serial
+	private static final long serialVersionUID = -2801001231345540040L;
 
 	/**
 	 * The