Description
dom4j before 2.0.3 and 2.1.x before 2.1.3 allows external DTDs and External Entities by default, which might enable XXE attacks. However, there is popular external documentation from OWASP showing how to enable the safe, non-default behavior in any application that uses dom4j.
Remediation
References
http://lists.opensuse.org/opensuse-security-announce/2020-05/msg00061.html
https://bugzilla.redhat.com/show_bug.cgi?id=1694235
https://cheatsheetseries.owasp.org/cheatsheets/XML_External_Entity_Prevention_Cheat_Sheet.html
https://github.com/dom4j/dom4j/commit/a8228522a99a02146106672a34c104adbda5c658
https://github.com/dom4j/dom4j/commits/version-2.0.3
https://github.com/dom4j/dom4j/issues/87
https://github.com/dom4j/dom4j/releases/tag/version-2.1.3
https://lists.apache.org/thread.html/r51f3f9801058e47153c0ad9bc6209d57a592fc0e7aefd787760911b8%40%3Cdev.velocity.apache.org%3E
https://lists.apache.org/thread.html/r91c64cd51e68e97d524395474eaa25362d564572276b9917fcbf5c32%40%3Cdev.velocity.apache.org%3E
https://lists.apache.org/thread.html/rb1b990d7920ae0d50da5109b73b92bab736d46c9788dd4b135cb1a51%40%3Cnotifications.freemarker.apache.org%3E
https://security.netapp.com/advisory/ntap-20200518-0002/
https://usn.ubuntu.com/4575-1/
https://www.oracle.com//security-alerts/cpujul2021.html
https://www.oracle.com/security-alerts/cpuApr2021.html
https://www.oracle.com/security-alerts/cpujan2021.html
https://www.oracle.com/security-alerts/cpujan2022.html
https://www.oracle.com/security-alerts/cpujul2020.html
https://www.oracle.com/security-alerts/cpujul2022.html
https://www.oracle.com/security-alerts/cpuoct2020.html
https://www.oracle.com/security-alerts/cpuoct2021.html
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