CVE-2021-3869: Improper Restriction of XML External Entity Reference in Stanford CoreNLP
Summary
CVE-2021-3869: Improper Restriction of XML External Entity Reference in Stanford CoreNLP. Affects edu.stanford.nlp:stanford-corenlp versions < 4.3.1. Fixed in 4.3.1. How to fix ↓
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Background
Stanford CoreNLP is an open-source natural language processing library developed by Stanford University. It provides a set of human language technology tools that can analyze and understand text. The library is widely used in various applications, including information extraction, sentiment analysis, and named entity recognition. However, versions of Stanford CoreNLP up to 4.3.0 are vulnerable to an improper restriction of XML external entity reference vulnerability.
Vulnerability Detail
The vulnerability in Stanford CoreNLP arises from its improper restriction of XML external entity references. This vulnerability allows an attacker to exploit the XML parsing functionality of the library to read arbitrary files from the server or cause a denial of service by initiating resource-intensive XML entity expansion attacks. An attacker can craft a malicious XML file that, when processed by the vulnerable CoreNLP version, triggers the external entity reference and leads to unauthorized access or resource exhaustion.
How To Fix
Latest published version: 4.6.0 as of 22 Oct 2026
Upgrading to it may include breaking changes; the version below is the minimum fixed release for this vulnerability.
If you need the minimum change
4.3.1
This is the first release that contains the fix.
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Workaround
There is no known workaround for this vulnerability. It is essential to update to the fixed version of Stanford CoreNLP to mitigate the risk.
Conclusion
The vulnerability in Stanford CoreNLP (CVE-2021-3869) exposes the application to potential unauthorized access and denial of service attacks. It is crucial to update to the fixed version (4.3.1 or later) to mitigate the risk. For further support on vulnerability remediation, please contact DevNack.com.
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FAQ
Stanford CoreNLP is an open-source natural language processing library developed by Stanford University. It provides a range of tools for analyzing and understanding text.
This vulnerability allows an attacker to read arbitrary files from the server or cause a denial of service by exploiting the XML parsing functionality of Stanford CoreNLP.
Versions up to 4.3.0 of Stanford CoreNLP are affected by this vulnerability.
No, there is no known workaround for this vulnerability. It is crucial to update to the fixed version of Stanford CoreNLP.
To fix this vulnerability, upgrade Stanford CoreNLP to version 4.3.1 or later.
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