commit 226809aebb345e74d371bb43a2b434b490be527a
Author: Ethan A Merritt <merritt@u.washington.edu>
Date:   Wed Jan 15 11:56:13 2025 -0800

    dumb:  more stringent tests against y bound of dumb terminal charcell array
    
    Bug 2756

diff --git term/dumb.trm term/dumb.trm
index 498e27fc6..fdc94fbf5 100644
--- term/dumb.trm
+++ term/dumb.trm
@@ -801,7 +801,7 @@ DUMB_put_text(unsigned int x, unsigned int y, const char *str)
 {
     int i, length;
 
-    if (y > dumb_ymax)
+    if (y < 0 || y > dumb_ymax)
 	return;
 
     length = gp_strlen(str);
@@ -949,7 +949,7 @@ ENHdumb_FLUSH()
 	y += i;
 
 	/* print the string fragment, perhaps invisibly */
-	if (ENHdumb_show && y < dumb_ymax) {
+	if (ENHdumb_show && (0 <= y && y < dumb_ymax)) {
 	    for (i = 0; i < len && x < dumb_xmax; i++, x++) {
 		utf8_copy_one( (char *)(&DUMB_PIXEL(x, y)), gp_strchrn(str,i));
 #ifndef NO_DUMB_COLOR_SUPPORT