CVE-2026-89044Netty 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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No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 6.5 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
- Weakness (CWE)
- CWE-444
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- VulnCheck
- NVD analysis
- Analyzed
- Record last updated
- Sep 18, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
netty netty netty:netty (from the name) | from 4.1.133.Final before 4.1.138.Final; from 4.2.13.Final before 4.2.18.Final | CNA record |
netty netty netty:netty | from 4.1.133 before 4.1.138; from 4.2.13 before 4.2.18 | NVD |
References
- https://github.com/netty/netty/security/advisories/GHSA-hcvj-94mj-jp5cvendor-advisory, exploit
- https://github.com/netty/netty/commit/ca87393b0e9e13c493d213a268e727a6d44e1585patch
- https://github.com/netty/netty/commit/640d4d3324f7b811a4903d0730c8ccb35500500cpatch
- https://github.com/netty/netty/blob/netty-4.1.137.Final/codec-http/src/main/java/io/netty/handler/codec/http/HttpObjectDecoder.java#L866technical-description, product
- https://github.com/netty/netty/releases/tag/netty-4.1.138.Finalrelease-notes
- https://github.com/netty/netty/releases/tag/netty-4.2.18.Finalrelease-notes
- https://github.com/netty/nettyproduct
- 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-encodingthird-party-advisory, patch
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.