From 5ca5aca48ec0428d16c282d62b5502358b2d5db3 Mon Sep 17 00:00:00 2001
From: Josh Cummings <3627351+jzheaux@users.noreply.github.com>
Date: Fri, 19 Sep 2025 17:45:29 -0600
Subject: [PATCH] Add Null Guard

Issue gh-17933
---
 .../preauth/PreAuthenticatedAuthenticationProvider.java          | 1 +
 1 file changed, 1 insertion(+)

diff --git a/web/src/main/java/org/springframework/security/web/authentication/preauth/PreAuthenticatedAuthenticationProvider.java b/web/src/main/java/org/springframework/security/web/authentication/preauth/PreAuthenticatedAuthenticationProvider.java
index 6c767b892e..945a5a6d68 100644
--- a/web/src/main/java/org/springframework/security/web/authentication/preauth/PreAuthenticatedAuthenticationProvider.java
+++ b/web/src/main/java/org/springframework/security/web/authentication/preauth/PreAuthenticatedAuthenticationProvider.java
@@ -157,6 +157,7 @@ public class PreAuthenticatedAuthenticationProvider implements AuthenticationPro
 	 * @param grantedAuthoritySupplier the supplier that grants authorities
 	 */
 	public void setGrantedAuthoritySupplier(Supplier<Collection<GrantedAuthority>> grantedAuthoritySupplier) {
+		Assert.notNull(grantedAuthoritySupplier, "grantedAuthoritySupplier cannot be null");
 		this.grantedAuthoritySupplier = grantedAuthoritySupplier;
 	}