From ca0859b90f0f3cb9bb369d38d29868de59796c2c Mon Sep 17 00:00:00 2001
From: Mae <Mae@is.badat.dev>
Date: Fri, 4 Aug 2023 22:24:17 +0100
Subject: [PATCH] Prevent XML parser from loading external entities

---
 lib/pleroma/web/xml.ex | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/lib/pleroma/web/xml.ex b/lib/pleroma/web/xml.ex
index b699446b0..380a80ab8 100644
--- a/lib/pleroma/web/xml.ex
+++ b/lib/pleroma/web/xml.ex
@@ -29,7 +29,10 @@ defmodule Pleroma.Web.XML do
       {doc, _rest} =
         text
         |> :binary.bin_to_list()
-        |> :xmerl_scan.string(quiet: true)
+        |> :xmerl_scan.string(
+          quiet: true,
+          fetch_fun: fn _, _ -> raise "Resolving external entities not supported" end
+        )
 
       {:ok, doc}
     rescue