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Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') in io.netty:netty-codec-http

CVE-2026-33870

  • io.netty:netty-codec-http
  • io.netty:netty-microbench
High
7.5/10

Summary

Netty is an asynchronous, event-driven network application framework. In 'netty-microbench' versions through 4.1.131.Final and 4.2.x through 4.2.10.Final and 'netty-codec-http' versions through 4.1.131.Final, 4.2.x through 4.2.10.Final and 5.0.0.Alpha1 through 5.0.0.Alpha2, Netty incorrectly parses quoted strings in HTTP/1.1 chunked transfer encoding extension values, enabling request smuggling attacks. Versions 4.1.132.Final and 4.2.11.Final fix the issue.

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