diff --git a/include/maxscale/utils.h b/include/maxscale/utils.h
index 55ce9a34e..67f699af2 100644
--- a/include/maxscale/utils.h
+++ b/include/maxscale/utils.h
@@ -72,7 +72,7 @@ char* replace_literal(char* haystack,
                       const char* replacement);
 char* replace_quoted(const char** src, const size_t* srcsize, char** dest, size_t* destsize);
 
-void clean_up_pathname(char *path);
+bool clean_up_pathname(char *path);
 
 bool mxs_mkdir_all(const char *path, int mask);
 
diff --git a/server/core/utils.c b/server/core/utils.c
index 0688da6c8..9a930def9 100644
--- a/server/core/utils.c
+++ b/server/core/utils.c
@@ -315,14 +315,15 @@ char *create_hex_sha1_sha1_passwd(char *passwd)
  * Remove duplicate and trailing forward slashes from a path.
  * @param path Path to clean up
  */
-void clean_up_pathname(char *path)
+bool clean_up_pathname(char *path)
 {
     char *data = path;
     size_t len = strlen(path);
 
     if (len > PATH_MAX)
     {
-        MXS_WARNING("Pathname too long: %s", path);
+        MXS_ERROR("Pathname too long: %s", path);
+        return false;
     }
 
     while (*data != '\0')
@@ -350,6 +351,8 @@ void clean_up_pathname(char *path)
             len--;
         }
     }
+
+    return true;
 }
 
 /**
diff --git a/server/modules/authenticator/MySQLAuth/mysql_auth.c b/server/modules/authenticator/MySQLAuth/mysql_auth.c
index a7942783d..a2fe41894 100644
--- a/server/modules/authenticator/MySQLAuth/mysql_auth.c
+++ b/server/modules/authenticator/MySQLAuth/mysql_auth.c
@@ -155,7 +155,8 @@ static void* mysql_auth_init(char **options)
 
                 if (strcmp(options[i], "cache_dir") == 0)
                 {
-                    if ((instance->cache_dir = MXS_STRDUP(value)) == NULL)
+                    if ((instance->cache_dir = MXS_STRDUP(value)) == NULL ||
+                        !clean_up_pathname(instance->cache_dir))
                     {
                         error = true;
                     }
@@ -903,7 +904,7 @@ static int mysql_auth_load_users(SERV_LISTENER *port)
 
     if (instance->cache_dir)
     {
-        strcpy(path, instance->cache_dir);
+        snprintf(path, sizeof(path) - sizeof(DBUSERS_FILE) - 1, "%s/", instance->cache_dir);
     }
     else
     {