1 files changed, 10 insertions, 0 deletions
diff --git a/lib/vtls/vtls.c b/lib/vtls/vtls.c
index a1a301e7f..52f922841 100644
--- a/lib/vtls/vtls.c
+++ b/lib/vtls/vtls.c
@@ -206,10 +206,20 @@ ssl_connect_init_proxy(struct connectdata *conn, int sockindex)
   DEBUGASSERT(conn->bits.proxy_ssl_connected[sockindex]);
   if(ssl_connection_complete == conn->ssl[sockindex].state &&
      !conn->proxy_ssl[sockindex].use) {
+    struct ssl_backend_data *pbdata;
+
     if(!Curl_ssl->support_https_proxy)
       return CURLE_NOT_BUILT_IN;
+
+    /* The pointers to the ssl backend data, which is opaque here, are swapped
+       rather than move the contents. */
+    pbdata = conn->proxy_ssl[sockindex].backend;
     conn->proxy_ssl[sockindex] = conn->ssl[sockindex];
+
     memset(&conn->ssl[sockindex], 0, sizeof(conn->ssl[sockindex]));
+    memset(pbdata, 0, Curl_ssl->sizeof_ssl_backend_data);
+
+    conn->ssl[sockindex].backend = pbdata;
   }
   return CURLE_OK;
 }