diff --git a/openbsc/src/libmsc/ctrl_commands.c b/openbsc/src/libmsc/ctrl_commands.c
index 9ac39de..0d6a37c 100644
--- a/openbsc/src/libmsc/ctrl_commands.c
+++ b/openbsc/src/libmsc/ctrl_commands.c
@@ -56,7 +56,7 @@
 
 	if (!imsi || !msisdn)
 		rc = 1;
-	else if (strlen(imsi) >= GSM_IMSI_LENGTH)
+	else if (strlen(imsi) > GSM23003_IMSI_MAX_DIGITS)
 		rc = 1;
 	else if (strlen(msisdn) >= GSM_EXTENSION_LENGTH)
 		rc = 1;