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Improper Restriction of XML External Entity Reference


Severity High
Score 9.8/10


In the XSS Protection API module before 1.0.12 in Apache Sling, the method XSS.getValidXML() uses an insecure SAX parser to validate the input string, which allows for XXE attacks in all scripts which use this method to validate user input, potentially allowing an attacker to read sensitive data on the filesystem, perform same-site-request-forgery (SSRF), port-scanning behind the firewall or DoS the application.

  • LOW
  • HIGH
  • NONE
  • NONE
  • HIGH
  • HIGH

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.


Advisory Timeline

  • Published