https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=6235

diff --git a/MagickCore/xml-tree.c b/MagickCore/xml-tree.c
index dfcfe8ccf7c436742e901fa1cfe5e9e482c04f9a..c19e85c6d30bc7dc937047fdb2392e46b04d0623 100644 (file)
--- a/MagickCore/xml-tree.c
+++ b/MagickCore/xml-tree.c
@@ -1721,6 +1721,8 @@ static MagickBooleanType ParseInternalDoctype(XMLTreeRoot *root,char *xml,
         /*
           Parse entity definitions.
         */
+        if (strspn(xml+8,XMLWhitespace) == 0)
+          break;
         xml+=strspn(xml+8,XMLWhitespace)+8;
         c=xml;
         n=xml+strspn(xml,XMLWhitespace "%");