diff --git a/lib/readkey.c b/lib/readkey.c
index a42d1cb..895db82 100644
--- a/lib/readkey.c
+++ b/lib/readkey.c
@@ -67,6 +67,8 @@
 				esc[i] = getc();
 				if (esc[i++] == '~')
 					break;
+				if (i == 5)
+					return -1;
 			}
 		}
 		esc[i] = 0;