Index: head/contrib/nvi/common/encoding.c
===================================================================
--- head/contrib/nvi/common/encoding.c
+++ head/contrib/nvi/common/encoding.c
@@ -96,7 +96,7 @@
 				if (i >= nbytes)
 					goto done;
 
-				if (buf[i] & 0x40)	/* 10xxxxxx */
+				if ((buf[i] & 0xc0) != 0x80)	/* 10xxxxxx */
 					return -1;
 			}