diff --git a/core/src/main/resources/jenkins/security/whitelisted-classes.txt b/core/src/main/resources/jenkins/security/whitelisted-classes.txt
index 3ad58670b65d..3ddb8d841a82 100644
--- a/core/src/main/resources/jenkins/security/whitelisted-classes.txt
+++ b/core/src/main/resources/jenkins/security/whitelisted-classes.txt
@@ -59,6 +59,7 @@ java.math.BigInteger
 java.net.URI
 java.net.URL
 java.security.KeyRep
+java.time.Ser
 java.util.ArrayDeque
 java.util.ArrayList
 java.util.Arrays$ArrayList