Improper Restriction of XML External Entity Reference
Elastic App Search versions from 7.11.0 prior to 7.12.1 contain an XML External Entity Injection issue (XXE) in the App Search web crawler beta feature. Using this vector, an attacker whose website is being crawled by App Search could craft a malicious sitemap.xml to traverse the filesystem of the host running the instance and obtain sensitive files.
CWE-611 - Improper Restriction of XML External Entity Reference
Listed 4th in the 'OWASP Top Ten', XML External Entities (XXE) vulnerability allows attackers to provide an XML input that contains an external entity. When the XML is parsed, it can cause data extraction and manipulation, execution of commands, denial-of-service attacks, and server-side request forgery.