# CVE-2026-89044

## Summary

- **CVE ID:** CVE-2026-89044
- **Severity:** MEDIUM
- **CVSS Score:** 6.9 (CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N)
- **CWE:** CWE-444
- **Published:** Sep 10, 2026
- **Last Modified:** Sep 10, 2026

## Description

Netty versions 4.1.133.Final through 4.1.137.Final and 4.2.13.Final through 4.2.17.Final fail to properly validate the final transfer coding in the Transfer-Encoding header, allowing attackers to smuggle requests by using malformed encoding declarations. Attackers can split Transfer-Encoding headers across multiple lines or use values like 'chunked, xchunked' to bypass validation and decode messages as chunked when the final coding is not chunked, enabling request smuggling attacks.

## Affected Products

- netty — netty (4.1.133.Final)
- netty — netty (4.2.13.Final)

## References

- [CNA](https://github.com/netty/netty/security/advisories/GHSA-hcvj-94mj-jp5c)
- [CNA](https://github.com/netty/netty/commit/ca87393b0e9e13c493d213a268e727a6d44e1585)
- [CNA](https://github.com/netty/netty/commit/640d4d3324f7b811a4903d0730c8ccb35500500c)
- [CNA](https://github.com/netty/netty/blob/netty-4.1.137.Final/codec-http/src/main/java/io/netty/handler/codec/http/HttpObjectDecoder.java#L866)
- [CNA](https://github.com/netty/netty/releases/tag/netty-4.1.138.Final)
- [CNA](https://github.com/netty/netty/releases/tag/netty-4.2.18.Final)
- [CNA](https://github.com/netty/netty)
- [CNA](https://www.vulncheck.com/advisories/netty-4.1.133-final-through-4.1.137-final-and-4.2.13-final-through-4.2.17-final-http-request-smuggling-via-transfer-encoding)

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-11._