There is a XML external entity expansion (XXE) vulnerability in Apache Solr config files
Moderate severity
GitHub Reviewed
Published
Oct 17, 2018
to the GitHub Advisory Database
•
Updated Mar 4, 2024
Package
Affected versions
>= 6.6.0, < 6.6.4
>= 7.0.0, < 7.3.1
Patched versions
6.6.4
7.3.1
Description
Published to the GitHub Advisory Database
Oct 17, 2018
Reviewed
Jun 16, 2020
Last updated
Mar 4, 2024
This vulnerability in Apache Solr 6.0.0 to 6.6.3, 7.0.0 to 7.3.0 relates to an XML external entity expansion (XXE) in Solr config files (solrconfig.xml, schema.xml, managed-schema). In addition, Xinclude functionality provided in these config files is also affected in a similar way. The vulnerability can be used as XXE using file/ftp/http protocols in order to read arbitrary local files from the Solr server or the internal network. Users are advised to upgrade to either Solr 6.6.4 or Solr 7.3.1 releases both of which address the vulnerability. Once upgrade is complete, no other steps are required. Those releases only allow external entities and Xincludes that refer to local files / zookeeper resources below the Solr instance directory (using Solr's ResourceLoader); usage of absolute URLs is denied. Keep in mind, that external entities and XInclude are explicitly supported to better structure config files in large installations. Before Solr 6 this was no problem, as config files were not accessible through the APIs.
References