2 files changed, 12 insertions, 0 deletions
diff --git a/man.c b/man.c
index f2031616..b14f9897 100644
--- a/man.c
+++ b/man.c
@@ -493,6 +493,12 @@ man_pmacro(struct man *m, int ln, char *buf)
 			break;
 		else if (' ' == buf[i])
 			break;
+
+		/* Check for invalid characters. */
+
+		if (isgraph((u_char)buf[i]))
+			continue;
+		return(man_perr(m, ln, i, WNPRINT));
 	}
 
 	mac[j] = 0;
diff --git a/mdoc.c b/mdoc.c
index f425d4f4..354a2e8f 100644
--- a/mdoc.c
+++ b/mdoc.c
@@ -709,6 +709,12 @@ parsemacro(struct mdoc *m, int ln, char *buf)
 			break;
 		else if (' ' == buf[i])
 			break;
+
+		/* Check for invalid characters. */
+
+		if (isgraph((u_char)buf[i]))
+			continue;
+		return(mdoc_perr(m, ln, i, EPRINT));
 	}
 
 	mac[j] = 0;