1 files changed, 4 insertions, 2 deletions
diff --git a/chars.c b/chars.c
index b1e7f487..95f0f6e6 100644
--- a/chars.c
+++ b/chars.c
@@ -113,7 +113,7 @@ mchars_num2char(const char *p, size_t sz)
 
 	if ((i = mandoc_strntoi(p, sz, 10)) < 0)
 		return('\0');
-	return(isprint(i) ? i : '\0');
+	return(i > 0 && i < 256 && isprint(i) ? i : '\0');
 }
 
 int
@@ -133,8 +133,10 @@ mchars_spec2str(struct mchars *arg, const char *p, size_t sz, size_t *rsz)
 	const struct ln	*ln;
 
 	ln = find(arg, p, sz);
-	if (NULL == ln)
+	if (NULL == ln) {
+		*rsz = 1;
 		return(NULL);
+	}
 
 	*rsz = strlen(ln->ascii);
 	return(ln->ascii);