From 92a212568403d985a2614a7d206bf34b7a8fb827 Mon Sep 17 00:00:00 2001
From: Daniel Stenberg <daniel@haxx.se>
Date: Mon, 6 Oct 2025 10:56:44 +0200
Subject: [PATCH] telnet: make bad_option() consider NULL a bad option too

Follow-up to a72e1552f22
Closes #18873
---
 lib/telnet.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/telnet.c b/lib/telnet.c
index 90316a446c..259a0c8931 100644
--- a/lib/telnet.c
+++ b/lib/telnet.c
@@ -930,7 +930,7 @@ static CURLcode check_telnet_options(struct Curl_easy *data,
    rather just ban its use instead */
 static bool bad_option(const char *data)
 {
-  return !!strchr(data, CURL_IAC);
+  return !data || !!strchr(data, CURL_IAC);
 }
 
 /*
-- 
2.47.3