diff --git a/src/buffer.c b/src/buffer.c
index 9856898..4016822 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -4617,6 +4617,8 @@
 #endif
 	if (vim_strchr(STL_ALL, *s) == NULL)
 	{
+	    if (*s == NUL)  // can happen with "%0"
+		break;
 	    s++;
 	    continue;
 	}