From 452b8e39ef3afce717395404bb9d62d497d3f5f6 Mon Sep 17 00:00:00 2001
From: Daniel Stenberg <daniel@haxx.se>
Date: Tue, 11 Apr 2023 09:22:08 +0200
Subject: [PATCH] http2: avoid possible null pointer dereference

Reported-by: Dan Fandrich
Fixes #10920
Closes #10923
---
 lib/http2.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/lib/http2.c b/lib/http2.c
index 3c9d0a014d..127ae4394f 100644
--- a/lib/http2.c
+++ b/lib/http2.c
@@ -219,13 +219,15 @@ static CURLcode http2_data_setup(struct Curl_cfilter *cf,
                                  struct stream_ctx **pstream)
 {
   struct cf_h2_ctx *ctx = cf->ctx;
-  struct stream_ctx *stream = H2_STREAM_CTX(data);
+  struct stream_ctx *stream;
 
   (void)cf;
+  DEBUGASSERT(data);
   if(!data->req.p.http) {
     failf(data, "initialization failure, transfer not http initialized");
     return CURLE_FAILED_INIT;
   }
+  stream = H2_STREAM_CTX(data);
   if(stream) {
     *pstream = stream;
     return CURLE_OK;