From d4ce595b1c95834b522fc8c3823305602f33ad79 Mon Sep 17 00:00:00 2001
From: Cristy <urban-warrior@imagemagick.org>
Date: Sat, 24 Feb 2018 09:02:35 -0500
Subject: [PATCH] https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=6533

---
 MagickCore/xml-tree.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/MagickCore/xml-tree.c b/MagickCore/xml-tree.c
index 0cfb02539..008ff5f3a 100644
--- a/MagickCore/xml-tree.c
+++ b/MagickCore/xml-tree.c
@@ -1726,6 +1726,8 @@ static MagickBooleanType ParseInternalDoctype(XMLTreeRoot *root,char *xml,
         xml+=strspn(xml+8,XMLWhitespace)+8;
         c=xml;
         n=xml+strspn(xml,XMLWhitespace "%");
+        if ((isalpha((int) ((unsigned char) *n)) == 0) && (*n != '_'))
+          break;
         xml=n+strcspn(n,XMLWhitespace);
         *xml=';';
         v=xml+strspn(xml+1,XMLWhitespace)+1;
-- 
2.40.0