diff --git a/src/core/ansi.c b/src/core/ansi.c
index 02bcd57..cf5de8b 100644
--- a/src/core/ansi.c
+++ b/src/core/ansi.c
@@ -1729,7 +1729,7 @@ ansi_send_pf(H3270 *hSession, int nn) {
 
 	if (nn < 1 || ((size_t) nn) > sizeof(code)/sizeof(code[0]))
 		return;
-	(void) sprintf(fn_buf, "\033[%d~", code[nn-1]);
+	(void) snprintf(fn_buf, sizeof(fn_buf), "\033[%d~", code[nn-1]);
 	net_sends(hSession,fn_buf);
 }
 
diff --git a/src/core/cursor.c b/src/core/cursor.c
index 51d5521..80d5284 100644
--- a/src/core/cursor.c
+++ b/src/core/cursor.c
@@ -90,7 +90,8 @@ LIB3270_EXPORT int lib3270_move_cursor(H3270 *hSession, LIB3270_DIRECTION dir, u
 			status_reset(hSession);
 		} else {
 			struct ta *ta = new_ta(hSession, TA_TYPE_CURSOR_MOVE);
-
+			if(!ta)
+				return -1;
 			ta->args.move.direction = dir;
 			ta->args.move.fn = lib3270_move_cursor;
 			ta->args.move.sel = sel;
diff --git a/src/core/keyboard/kybd.c b/src/core/keyboard/kybd.c
index f168265..71aab62 100644
--- a/src/core/keyboard/kybd.c
+++ b/src/core/keyboard/kybd.c
@@ -128,14 +128,16 @@ static const char dxl[] = "0123456789abcdef";
  * Check for typeahead availability and create a new TA structure.
  *
  * @return new typeahead struct or NULL if it's not available.
+ * @retval NULL Host is not connected or malloc error.
  */
 struct ta * new_ta(H3270 *hSession, enum _ta_type type) {
-	struct ta *ta;
+	struct ta *ta = NULL;
 
 	// If no connection, forget it.
 	if (!lib3270_is_connected(hSession)) {
 		lib3270_ring_bell(hSession);
 		lib3270_write_event_trace(hSession,"typeahead action dropped (not connected)\n");
+		errno = ENOTCONN;
 		return NULL;
 	}
 
@@ -143,6 +145,7 @@ struct ta * new_ta(H3270 *hSession, enum _ta_type type) {
 	if (hSession->kybdlock & KL_OERR_MASK) {
 		lib3270_ring_bell(hSession);
 		lib3270_write_event_trace(hSession,"typeahead action dropped (operator error)\n");
+		errno = EINVAL;
 		return NULL;
 	}
 
@@ -150,6 +153,7 @@ struct ta * new_ta(H3270 *hSession, enum _ta_type type) {
 	if (hSession->kybdlock & KL_SCROLLED) {
 		lib3270_ring_bell(hSession);
 		lib3270_write_event_trace(hSession,"typeahead action dropped (scrolled)\n");
+		errno = EINVAL;
 		return NULL;
 	}
 
@@ -157,6 +161,7 @@ struct ta * new_ta(H3270 *hSession, enum _ta_type type) {
 	if (!hSession->typeahead) {
 		lib3270_ring_bell(hSession);
 		lib3270_write_event_trace(hSession,"typeahead action dropped (no typeahead)\n");
+		errno = EINVAL;
 		return NULL;
 	}
 
diff --git a/src/core/see.c b/src/core/see.c
index e2fc858..8d6fa84 100644
--- a/src/core/see.c
+++ b/src/core/see.c
@@ -180,47 +180,47 @@ const char * see_attr(unsigned char fa) {
 	buf[0] = '\0';
 
 	if (fa & FA_PROTECT) {
-		(void) strcat(buf, paren);
-		(void) strcat(buf, "protected");
+		(void) strncat(buf, paren, 255);
+		(void) strncat(buf, "protected", 255);
 		paren = ",";
 		if (fa & FA_NUMERIC) {
-			(void) strcat(buf, paren);
-			(void) strcat(buf, "skip");
+			(void) strncat(buf, paren, 255);
+			(void) strncat(buf, "skip", 255);
 			paren = ",";
 		}
 	} else if (fa & FA_NUMERIC) {
-		(void) strcat(buf, paren);
-		(void) strcat(buf, "numeric");
+		(void) strncat(buf, paren, 255);
+		(void) strncat(buf, "numeric", 255);
 		paren = ",";
 	}
 	switch (fa & FA_INTENSITY) {
 	case FA_INT_NORM_NSEL:
 		break;
 	case FA_INT_NORM_SEL:
-		(void) strcat(buf, paren);
-		(void) strcat(buf, "detectable");
+		(void) strncat(buf, paren, 255);
+		(void) strncat(buf, "detectable", 255);
 		paren = ",";
 		break;
 	case FA_INT_HIGH_SEL:
-		(void) strcat(buf, paren);
-		(void) strcat(buf, "intensified");
+		(void) strncat(buf, paren, 255);
+		(void) strncat(buf, "intensified", 255);
 		paren = ",";
 		break;
 	case FA_INT_ZERO_NSEL:
-		(void) strcat(buf, paren);
-		(void) strcat(buf, "nondisplay");
+		(void) strncat(buf, paren, 255);
+		(void) strncat(buf, "nondisplay", 255);
 		paren = ",";
 		break;
 	}
 	if (fa & FA_MODIFY) {
-		(void) strcat(buf, paren);
-		(void) strcat(buf, "modified");
+		(void) strncat(buf, paren, 255);
+		(void) strncat(buf, "modified", 255);
 		paren = ",";
 	}
 	if (strcmp(paren, "("))
-		(void) strcat(buf, ")");
+		(void) strncat(buf, ")", 255);
 	else
-		(void) strcpy(buf, "(default)");
+		(void) strncpy(buf, "(default)", 255);
 
 	return buf;
 }
--
libgit2 0.21.2