CVE-2021-41098: Improper Restriction of XML External Entity Reference (XXE) in Nokogiri on JRuby
Severity
The Nokogiri maintainers have evaluated this as High Severity 7.5 (CVSS3.0) for JRuby users. (This security advisory does not apply to CRuby users.)
Impact
In Nokogiri v1.12.4 and earlier, on JRuby only, the SAX parser resolves external entities by default.
Users of Nokogiri on JRuby who parse untrusted documents using any of these classes are affected:
- Nokogiri::XML::SAX::Parser - Nokogiri::HTML4::SAX::Parser or its alias Nokogiri::HTML::SAX::Parser - Nokogiri::XML::SAX::PushParser - Nokogiri::HTML4::SAX::PushParser or its alias Nokogiri::HTML::SAX::PushParser
Mitigation
JRuby users should upgrade to Nokogiri v1.12.5 or later. There are no workarounds available for v1.12.4 or earlier.
CRuby users are not affected.
Other sources
Nokogiri is a Rubygem providing HTML, XML, SAX, and Reader parsers with XPath and CSS selector support. In Nokogiri v1.12.4 and earlier, on JRuby only, the SAX parser resolves external entities by default. Users of Nokogiri on JRuby who parse untrusted documents using any of these classes are affected: Nokogiri::XML::SAX::Parse, Nokogiri::HTML4::SAX::Parser or its alias Nokogiri::HTML::SAX::Parser, Nokogiri::XML::SAX::PushParser, and Nokogiri::HTML4::SAX::PushParser or its alias Nokogiri::HTML::SAX::PushParser. JRuby users should upgrade to Nokogiri v1.12.5 or later to receive a patch for this issue. There are no workarounds available for v1.12.4 or earlier. CRuby users are not affected.
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2021-41098?
The severity of CVE-2021-41098 is high with a CVSS3.0 score of 7.5.
Which software is affected by CVE-2021-41098?
Nokogiri Rubygem versions up to and including 1.12.4 and Nokogiri Nokogiri versions up to but excluding 1.12.5 are affected by CVE-2021-41098.
How can I fix CVE-2021-41098?
To fix CVE-2021-41098, upgrade to Nokogiri version 1.12.5 or later.
Is CRuby affected by CVE-2021-41098?
No, this security advisory does not apply to CRuby users.
Where can I find more information about CVE-2021-41098?
You can find more information about CVE-2021-41098 on the [Nokogiri GitHub Security Advisory](https://github.com/sparklemotion/nokogiri/security/advisories/GHSA-2rr5-8q37-2w7h) and [NVD](https://nvd.nist.gov/vuln/detail/CVE-2021-41098) websites.