1 files changed, 1 insertions, 1 deletions
diff --git a/tiffer.h b/tiffer.h
index 1122773..b4e582e 100644
--- a/tiffer.h
+++ b/tiffer.h
@@ -161,7 +161,7 @@ static bool
 tiffer_subifd(
 	const struct tiffer *self, uint32_t offset, struct tiffer *subreader)
 {
-	if (self->end - self->begin < offset)
+	if (self->begin > self->end || self->end - self->begin < offset)
 		return false;
 
 	*subreader = *self;