diff --git a/common/xrdp_client_info.h b/common/xrdp_client_info.h
index 297cdc55..fa7df6bf 100644
--- a/common/xrdp_client_info.h
+++ b/common/xrdp_client_info.h
@@ -18,6 +18,8 @@
  * xrdp / xserver info / caps
  */
 
+#include "xrdp_constants.h"
+
 #if !defined(XRDP_CLIENT_INFO_H)
 #define XRDP_CLIENT_INFO_H
 
@@ -57,11 +59,11 @@ struct xrdp_client_info
   char hostname[32];
   int build;
   int keylayout;
-  char username[256];
-  char password[256];
-  char domain[256];
-  char program[256];
-  char directory[256];
+  char username[INFO_CLIENT_MAX_CB_LEN];
+  char password[INFO_CLIENT_MAX_CB_LEN];
+  char domain[INFO_CLIENT_MAX_CB_LEN];
+  char program[INFO_CLIENT_MAX_CB_LEN];
+  char directory[INFO_CLIENT_MAX_CB_LEN];
   int rdp_compression;
   int rdp_autologin;
   int crypt_level; /* 1, 2, 3 = low, medium, high */
diff --git a/common/xrdp_constants.h b/common/xrdp_constants.h
index 93ca2086..7b777e3d 100644
--- a/common/xrdp_constants.h
+++ b/common/xrdp_constants.h
@@ -38,6 +38,11 @@
  ******************************************************************************/
 
 #define INFO_CLIENT_NAME_BYTES  32
+/**
+ * Maximum length of a string including the mandatory null terminator
+ * [MS-RDPBCGR] TS_INFO_PACKET(2.2.1.11.1.1)
+ */
+#define INFO_CLIENT_MAX_CB_LEN  512
 
 #define XRDP_MAX_BITMAP_CACHE_ID  3
 #define XRDP_MAX_BITMAP_CACHE_IDX 2000
diff --git a/libxrdp/xrdp_sec.c b/libxrdp/xrdp_sec.c
index c0e513e4..4ce0d509 100644
--- a/libxrdp/xrdp_sec.c
+++ b/libxrdp/xrdp_sec.c
@@ -735,7 +735,7 @@ xrdp_sec_process_logon_info(struct xrdp_sec *self, struct stream *s)
     }
     in_uint16_le(s, len_domain);
 
-    if (len_domain > 511)
+    if (len_domain >= INFO_CLIENT_MAX_CB_LEN)
     {
         DEBUG(("ERROR [xrdp_sec_process_logon_info()]: len_domain > 511"));
         return 1;
@@ -757,7 +757,7 @@ xrdp_sec_process_logon_info(struct xrdp_sec *self, struct stream *s)
         self->rdp_layer->client_info.rdp_autologin = 0;
     }
 
-    if (len_user > 511)
+    if (len_user >= INFO_CLIENT_MAX_CB_LEN)
     {
         DEBUG(("ERROR [xrdp_sec_process_logon_info()]: len_user > 511"));
         return 1;
@@ -769,7 +769,7 @@ xrdp_sec_process_logon_info(struct xrdp_sec *self, struct stream *s)
     }
     in_uint16_le(s, len_password);
 
-    if (len_password > 511)
+    if (len_password >= INFO_CLIENT_MAX_CB_LEN)
     {
         DEBUG(("ERROR [xrdp_sec_process_logon_info()]: len_password > 511"));
         return 1;
@@ -781,7 +781,7 @@ xrdp_sec_process_logon_info(struct xrdp_sec *self, struct stream *s)
     }
     in_uint16_le(s, len_program);
 
-    if (len_program > 511)
+    if (len_program >= INFO_CLIENT_MAX_CB_LEN)
     {
         DEBUG(("ERROR [xrdp_sec_process_logon_info()]: len_program > 511"));
         return 1;
@@ -793,7 +793,7 @@ xrdp_sec_process_logon_info(struct xrdp_sec *self, struct stream *s)
     }
     in_uint16_le(s, len_directory);
 
-    if (len_directory > 511)
+    if (len_directory >= INFO_CLIENT_MAX_CB_LEN)
     {
         DEBUG(("ERROR [xrdp_sec_process_logon_info()]: len_directory > 511"));
         return 1;
diff --git a/neutrinordp/xrdp-neutrinordp.h b/neutrinordp/xrdp-neutrinordp.h
index b68eb43a..f50a299e 100644
--- a/neutrinordp/xrdp-neutrinordp.h
+++ b/neutrinordp/xrdp-neutrinordp.h
@@ -24,6 +24,7 @@
 #include "defines.h"
 #include "xrdp_rail.h"
 #include "xrdp_client_info.h"
+#include "xrdp_constants.h"
 
 /* this is the freerdp main header */
 #include <freerdp/freerdp.h>
@@ -196,9 +197,9 @@ struct mod
     int vmaj;
     int vmin;
     int vrev;
-    char username[256];
-    char password[256];
-    char domain[256];
+    char username[INFO_CLIENT_MAX_CB_LEN];
+    char password[INFO_CLIENT_MAX_CB_LEN];
+    char domain[INFO_CLIENT_MAX_CB_LEN];
     int bool_keyBoardSynced ; /* Numlock can be out of sync, we hold state here to resolve */
     int keyBoardLockInfo ; /* Holds initial numlock capslock state */
 
diff --git a/sesman/verify_user_pam.c b/sesman/verify_user_pam.c
index 05e941bb..312bcbc8 100644
--- a/sesman/verify_user_pam.c
+++ b/sesman/verify_user_pam.c
@@ -34,10 +34,13 @@
 #include <stdio.h>
 #include <security/pam_appl.h>
 
+/* Defines the maximum size of a username or password. With pam there is no real limit */
+#define MAX_BUF 8192
+
 struct t_user_pass
 {
-    char user[256];
-    char pass[256];
+    char user[MAX_BUF];
+    char pass[MAX_BUF];
 };
 
 struct t_auth_info
@@ -115,8 +118,8 @@ auth_userpass(const char *user, const char *pass, int *errorcode)
 
     get_service_name(service_name);
     auth_info = g_new0(struct t_auth_info, 1);
-    g_strncpy(auth_info->user_pass.user, user, 255);
-    g_strncpy(auth_info->user_pass.pass, pass, 255);
+    g_strncpy(auth_info->user_pass.user, user, MAX_BUF - 1);
+    g_strncpy(auth_info->user_pass.pass, pass, MAX_BUF - 1);
     auth_info->pamc.conv = &verify_pam_conv;
     auth_info->pamc.appdata_ptr = &(auth_info->user_pass);
     error = pam_start(service_name, 0, &(auth_info->pamc), &(auth_info->ph));
diff --git a/xup/xup.c b/xup/xup.c
index e6321651..a235194b 100644
--- a/xup/xup.c
+++ b/xup/xup.c
@@ -1546,11 +1546,11 @@ lib_mod_set_param(struct mod *mod, const char *name, const char *value)
 {
     if (g_strcasecmp(name, "username") == 0)
     {
-        g_strncpy(mod->username, value, 255);
+        g_strncpy(mod->username, value, INFO_CLIENT_MAX_CB_LEN-1);
     }
     else if (g_strcasecmp(name, "password") == 0)
     {
-        g_strncpy(mod->password, value, 255);
+        g_strncpy(mod->password, value, INFO_CLIENT_MAX_CB_LEN-1);
     }
     else if (g_strcasecmp(name, "ip") == 0)
     {
diff --git a/xup/xup.h b/xup/xup.h
index ddd24e36..f7de3a17 100644
--- a/xup/xup.h
+++ b/xup/xup.h
@@ -24,6 +24,7 @@
 #include "os_calls.h"
 #include "defines.h"
 #include "xrdp_client_info.h"
+#include "xrdp_constants.h"
 #include "xrdp_rail.h"
 
 #define CURRENT_MOD_VER 4
@@ -154,8 +155,8 @@ struct mod
   int height;
   int bpp;
   int sck_closed;
-  char username[256];
-  char password[256];
+  char username[INFO_CLIENT_MAX_CB_LEN];
+  char password[INFO_CLIENT_MAX_CB_LEN];
   char ip[256];
   char port[256];
   int shift_state;