diff --git a/src/gsm/gsm0480.c b/src/gsm/gsm0480.c
index 38082b3..636f267 100644
--- a/src/gsm/gsm0480.c
+++ b/src/gsm/gsm0480.c
@@ -552,8 +552,12 @@
 	if (num_chars > length - 2)
 		return 0;
 
-	if (num_chars > GSM0480_USSD_OCTET_STRING_LEN)
-		num_chars = GSM0480_USSD_OCTET_STRING_LEN;
+	/* Drop messages with incorrect length */
+	if (num_chars > GSM0480_USSD_OCTET_STRING_LEN) {
+		LOGP(DLGLOBAL, LOGL_ERROR, "Incorrect USS_DATA data length=%u, "
+			"dropping message", num_chars);
+		return 0;
+	}
 
 	memcpy(req->ussd_text, uss_req_data + 2, num_chars);
 
@@ -588,9 +592,12 @@
 	/* Get the amount of bytes */
 	num_chars = uss_req_data[6];
 
-	/* Prevent a mobile-originated buffer-overrun! */
-	if (num_chars > GSM0480_USSD_OCTET_STRING_LEN)
-		num_chars = GSM0480_USSD_OCTET_STRING_LEN;
+	/* Drop messages with incorrect length */
+	if (num_chars > GSM0480_USSD_OCTET_STRING_LEN) {
+		LOGP(DLGLOBAL, LOGL_ERROR, "Incorrect USS_REQ data length=%u, "
+			"dropping message", num_chars);
+		return 0;
+	}
 
 	/* Copy the data 'as is' */
 	memcpy(req->ussd_data, uss_req_data + 7, num_chars);
@@ -606,10 +613,6 @@
 		/* Calculate the amount of 7-bit characters */
 		num_chars = (num_chars * 8) / 7;
 
-		/* Prevent a mobile-originated buffer-overrun! */
-		if (num_chars > GSM0480_USSD_7BIT_STRING_LEN)
-			num_chars = GSM0480_USSD_7BIT_STRING_LEN;
-
 		gsm_7bit_decode_n_ussd((char *)req->ussd_text,
 			sizeof(req->ussd_text), &(uss_req_data[7]), num_chars);