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Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

CVE-2019-17569

Medium
4.8/10

Summary

The refactoring present in Apache Tomcat before 8.5.51 and 9.x before 9.0.31 introduced a regression. The result of the regression was that invalid Transfer-Encoding headers were incorrectly processed leading to a possibility of HTTP Request Smuggling if Tomcat was located behind a reverse proxy that incorrectly handled the invalid Transfer-Encoding header in a particular manner. Such a reverse proxy is considered unlikely.

  • HIGH
  • NETWORK
  • LOW
  • UNCHANGED
  • NONE
  • NONE
  • LOW
  • NONE

CWE-444 - HTTP Request Smuggling

Entities such as web servers, web caching proxies, and application firewalls could parse HTTP requests differently. When there are two or more such entities in the path of an HTTP request, an attacker can send a specially crafted HTTP request that is seen as two different sets of requests by the attacked devices, allowing the attacker to smuggle a request into one device without the other device being aware of it. Such a vulnerability can prove devastating, for it enables further attacks on the application, like web cache poisoning, session hijacking, cross-site scripting, security bypassing, and sensitive information exposure.

References

Advisory Timeline

  • Published