diff --git a/src/main/java/fr/plil/sio/web/mvc/SecurityServiceImpl.java b/src/main/java/fr/plil/sio/web/mvc/SecurityServiceImpl.java
index ebdc49b..f143f14 100644
--- a/src/main/java/fr/plil/sio/web/mvc/SecurityServiceImpl.java
+++ b/src/main/java/fr/plil/sio/web/mvc/SecurityServiceImpl.java
@@ -3,6 +3,7 @@ package fr.plil.sio.web.mvc;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+import org.springframework.security.core.Authentication;
 import org.springframework.security.core.context.SecurityContextHolder;
 import org.springframework.security.core.userdetails.UserDetails;
 import org.springframework.stereotype.Service;
@@ -14,10 +15,18 @@ public class SecurityServiceImpl implements SecurityService{
 
     @Override
     public String findLoggedInUsername() {
-        Object userDetails = SecurityContextHolder.getContext().getAuthentication().getPrincipal();
-        if (userDetails instanceof UserDetails) {
-            return ((UserDetails)userDetails).getUsername();
+        Authentication authentication = SecurityContextHolder.getContext().getAuthentication();
+
+        if(authentication == null) {
+            return null;
         }
+
+        Object principal = authentication.getPrincipal();
+
+        if (principal instanceof UserDetails) {
+            return ((UserDetails)principal).getUsername();
+        }
+
         logger.warn("cannot find logged user");
         return null;
     }
--
libgit2 0.21.2