diff --git a/usr.bin/grep/file.c b/usr.bin/grep/file.c
index 3d86bef010e5..8577572c2887 100644
--- a/usr.bin/grep/file.c
+++ b/usr.bin/grep/file.c
@@ -98,7 +98,6 @@ char *
 grep_fgetln(struct file *f, struct parsec *pc)
 {
 	char *p;
-	char *ret;
 	size_t len;
 	size_t off;
 	ptrdiff_t diff;
@@ -116,12 +115,15 @@ grep_fgetln(struct file *f, struct parsec *pc)
 	/* Look for a newline in the remaining part of the buffer */
 	if ((p = memchr(bufpos, fileeol, bufrem)) != NULL) {
 		++p; /* advance over newline */
-		ret = bufpos;
 		len = p - bufpos;
+		if (grep_lnbufgrow(len + 1))
+			goto error;
+		memcpy(lnbuf, bufpos, len);
 		bufrem -= len;
 		bufpos = p;
 		pc->ln.len = len;
-		return (ret);
+		lnbuf[len] = '\0';
+		return (lnbuf);
 	}
 
 	/* We have to copy the current buffered data to the line buffer */
@@ -148,7 +150,7 @@ grep_fgetln(struct file *f, struct parsec *pc)
 		++p;
 		diff = p - bufpos;
 		len += diff;
-		if (grep_lnbufgrow(len))
+		if (grep_lnbufgrow(len + 1))
 		    goto error;
 		memcpy(lnbuf + off, bufpos, diff);
 		bufrem -= diff;
@@ -156,6 +158,7 @@ grep_fgetln(struct file *f, struct parsec *pc)
 		break;
 	}
 	pc->ln.len = len;
+	lnbuf[len] = '\0';
 	return (lnbuf);
 
 error:
diff --git a/usr.bin/grep/queue.c b/usr.bin/grep/queue.c
index ac15185f0694..9babdbf74af8 100644
--- a/usr.bin/grep/queue.c
+++ b/usr.bin/grep/queue.c
@@ -95,12 +95,14 @@ enqueue(struct str *x)
 		rotated = true;
 		free(item->dat);
 	}
-	item->dat = grep_malloc(sizeof(char) * x->len);
+	/* len + 1 for NUL-terminator */
+	item->dat = grep_malloc(sizeof(char) * x->len + 1);
 	item->len = x->len;
 	item->line_no = x->line_no;
 	item->boff = x->boff;
 	item->off = x->off;
 	memcpy(item->dat, x->dat, x->len);
+	item->dat[x->len] = '\0';
 	item->file = x->file;
 
 	return (rotated);