From 41e701ad8408a3411bb59198a067c4ef471abba8 Mon Sep 17 00:00:00 2001
From: Nicholas Marriott <nicholas.marriott@gmail.com>
Date: Mon, 24 Aug 2026 15:27:25 +0100
Subject: [PATCH] Return early if image is zero height when generating
 fallback, otherwise we can allocated too little space. Reported by Vivek
 Parikh.

---
 image.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/image.c b/image.c
index f0543dc4f..5613cf920 100644
--- a/image.c
+++ b/image.c
@@ -84,6 +84,11 @@ image_fallback(char **ret, u_int sx, u_int sy)
 	char	*buf, *label;
 	u_int	 py, size, lsize;
 
+	if (sy == 0) {
+		*ret = xstrdup("");
+		return;
+	}
+
 	/* Allocate first line. */
 	lsize = xasprintf(&label, "SIXEL IMAGE (%ux%u)\r\n", sx, sy) + 1;
 	if (sx < lsize - 3)