diff --git a/lib/cf-h2-proxy.c b/lib/cf-h2-proxy.c
index 038952d641..e687dd1050 100644
--- a/lib/cf-h2-proxy.c
+++ b/lib/cf-h2-proxy.c
@@ -277,6 +277,8 @@ static int proxy_h2_client_new(struct Curl_cfilter *cf,
 {
   struct cf_h2_proxy_ctx *ctx = cf->ctx;
   nghttp2_option *o;
+  nghttp2_mem mem = {NULL, Curl_nghttp2_malloc, Curl_nghttp2_free,
+                     Curl_nghttp2_calloc, Curl_nghttp2_realloc};
 
   int rc = nghttp2_option_new(&o);
   if(rc)
@@ -289,7 +291,7 @@ static int proxy_h2_client_new(struct Curl_cfilter *cf,
      HTTP field value. */
   nghttp2_option_set_no_rfc9113_leading_and_trailing_ws_validation(o, 1);
 #endif
-  rc = nghttp2_session_client_new2(&ctx->h2, cbs, cf, o);
+  rc = nghttp2_session_client_new3(&ctx->h2, cbs, cf, o, &mem);
   nghttp2_option_del(o);
   return rc;
 }
diff --git a/lib/http2.c b/lib/http2.c
index f1ee0cf9ec..dbe6f1aaae 100644
--- a/lib/http2.c
+++ b/lib/http2.c
@@ -433,6 +433,8 @@ static int h2_client_new(struct Curl_cfilter *cf,
 {
   struct cf_h2_ctx *ctx = cf->ctx;
   nghttp2_option *o;
+  nghttp2_mem mem = {NULL, Curl_nghttp2_malloc, Curl_nghttp2_free,
+                     Curl_nghttp2_calloc, Curl_nghttp2_realloc};
 
   int rc = nghttp2_option_new(&o);
   if(rc)
@@ -445,7 +447,7 @@ static int h2_client_new(struct Curl_cfilter *cf,
      HTTP field value. */
   nghttp2_option_set_no_rfc9113_leading_and_trailing_ws_validation(o, 1);
 #endif
-  rc = nghttp2_session_client_new2(&ctx->h2, cbs, cf, o);
+  rc = nghttp2_session_client_new3(&ctx->h2, cbs, cf, o, &mem);
   nghttp2_option_del(o);
   return rc;
 }
@@ -2960,6 +2962,30 @@ bool Curl_h2_http_1_1_error(struct Curl_easy *data)
   return FALSE;
 }
 
+void *Curl_nghttp2_malloc(size_t size, void *user_data)
+{
+  (void)user_data;
+  return Curl_cmalloc(size);
+}
+
+void Curl_nghttp2_free(void *ptr, void *user_data)
+{
+  (void)user_data;
+  Curl_cfree(ptr);
+}
+
+void *Curl_nghttp2_calloc(size_t nmemb, size_t size, void *user_data)
+{
+  (void)user_data;
+  return Curl_ccalloc(nmemb, size);
+}
+
+void *Curl_nghttp2_realloc(void *ptr, size_t size, void *user_data)
+{
+  (void)user_data;
+  return Curl_crealloc(ptr, size);
+}
+
 #else /* !USE_NGHTTP2 */
 
 /* Satisfy external references even if http2 is not compiled in. */
diff --git a/lib/http2.h b/lib/http2.h
index 80e183480a..dbb1784661 100644
--- a/lib/http2.h
+++ b/lib/http2.h
@@ -60,6 +60,11 @@ CURLcode Curl_http2_upgrade(struct Curl_easy *data,
                             struct connectdata *conn, int sockindex,
                             const char *ptr, size_t nread);
 
+void *Curl_nghttp2_malloc(size_t size, void *user_data);
+void Curl_nghttp2_free(void *ptr, void *user_data);
+void *Curl_nghttp2_calloc(size_t nmemb, size_t size, void *user_data);
+void *Curl_nghttp2_realloc(void *ptr, size_t size, void *user_data);
+
 extern struct Curl_cftype Curl_cft_nghttp2;
 
 #else /* USE_NGHTTP2 */