diff --git a/src/kiss.c b/src/kiss.c
index 40052cd..d2d158a 100644
--- a/src/kiss.c
+++ b/src/kiss.c
@@ -28,6 +28,8 @@ int patty_kiss_read(int fd, void *buf, size_t *len, int *channel) {
                 ((char *)buf)[b++] = PATTY_KISS_FEND;
             } else if (c == PATTY_KISS_TFESC) {
                 ((char *)buf)[b++] = PATTY_KISS_FESC;
+            } else {
+                goto error_io;
             }
 
             flags &= ~KISS_ESCAPE;
@@ -53,4 +55,7 @@ int patty_kiss_read(int fd, void *buf, size_t *len, int *channel) {
     *len = b + 1;
 
     return 0;
+
+error_io:
+    return -1;
 }