CVE-2021-21409
Publication date 30 March 2021
Last updated 26 August 2025
Ubuntu priority
Description
Netty is an open-source, asynchronous event-driven network application framework for rapid development of maintainable high performance protocol servers & clients. In Netty (io.netty:netty-codec-http2) before version 4.1.61.Final there is a vulnerability that enables request smuggling. The content-length header is not correctly validated if the request only uses a single Http2HeaderFrame with the endStream set to to true. This could lead to request smuggling if the request is proxied to a remote peer and translated to HTTP/1.1. This is a followup of GHSA-wm47-8v5p-wjpj/CVE-2021-21295 which did miss to fix this one case. This was fixed as part of 4.1.61.Final.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| netty | 25.10 questing |
Fixed 4.1.48-4
|
| 25.04 plucky |
Fixed 4.1.48-4
|
|
| 24.04 LTS noble |
Fixed 4.1.48-4
|
|
| 22.04 LTS jammy |
Fixed 1:4.1.48-4+deb11u1build0.22.04.1
|
|
| 20.04 LTS focal |
Fixed 1:4.1.45-1ubuntu0.1~esm1
|
|
| 18.04 LTS bionic |
Fixed 1:4.1.7-4ubuntu0.1+esm2
|
|
| 16.04 LTS xenial |
Fixed 1:4.0.34-1ubuntu0.1~esm1
|
|
| 14.04 LTS trusty |
Needs evaluation
|
Get expanded security coverage with Ubuntu Pro
Reduce your average CVE exposure time from 98 days to 1 day with expanded CVE patching, ten-years security maintenance and optional support for the full stack of open-source applications. Free for personal use.
Get Ubuntu Pro 30-day free trialSeverity score breakdown
| Parameter | Value |
|---|---|
| Base score |
5.9 · Medium
|
| Attack vector | Network |
| Attack complexity | High |
| Privileges required | None |
| User interaction | None |
| Scope | Unchanged |
| Confidentiality | None |
| Integrity impact | High |
| Availability impact | None |
| Vector | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N |
References
Related Ubuntu Security Notices (USN)
- USN-6049-1
- Netty vulnerabilities
- 28 April 2023