Nokogiri v1.12.5 was released on 2021-09-27 which contains a fix
for CVE-2021-41098, fully described at
Improper Restriction of XML External Entity Reference (XXE) in Nokogiri on JRuby · Advisory · sparklemotion/nokogiri · GitHub.
That advisory is reproduced here for your convenience.
The Nokogiri maintainers have evaluated this as High Severity 7.5 (CVSS3.0)
<Common Vulnerability Scoring System Version 3.0 Calculator>
JRuby users. (This security advisory does not apply to CRuby users.)
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::HTML4::SAX::Parser or its alias Nokogiri::HTML::SAX::Parser
- Nokogiri::HTML4::SAX::PushParser or its alias
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.
This vulnerability was reported by Andrew Crewdson
CWE - CWE-611: Improper Restriction of XML External Entity Reference (4.5)
<CWE - CWE-611: Improper Restriction of XML External Entity Reference (4.5)>
For more information
- XML External Entity (XXE) Processing | OWASP
- A4:2017-XML External Entities (XXE) | OWASP
- XML External Entity Prevention - OWASP Cheat Sheet Series
<XML External Entity Prevention - OWASP Cheat Sheet Series>