Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, HttpObjectDecoder strips a conflicting Content-Length header when a request carries both Transfer-Encoding: chunked and Content-Length, but only for HTTP/1.1 messages. The guard is absent for HTTP/1.0. An attacker that sends an HTTP/1.0 request with both headers causes Netty to decode the body as chunked while leaving Content-Length intact in the forwarded HttpMessage. Any downstream proxy or handler that trusts Content-Length over Transfer-Encoding will disagree on message boundaries, enabling request smuggling. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.
| Vendor | Product | Versions |
|---|---|---|
| netty | netty | >= 4.2.0.Alpha1, < 4.2.13.Final, < 4.1.133.Final |
Downstream vendors/products affected by this vulnerability
| Vendor | Product | Source | Confidence |
|---|---|---|---|
| atlassian | confluence | cert_advisory | 90% |
| atlassian | fisheye | cert_advisory | 90% |
| atlassian | jira | cert_advisory | 90% |
| atlassian | bitbucket | cert_advisory | 90% |
| atlassian | bamboo | cert_advisory | 90% |
Updated severity to HIGH, marked as actively exploited, and added CVE-2026-42581 as a new tag.
Initial creation
