CVSS 4.0
6.9 mediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:NCVE-2026-89044
Medium (6.9) in netty netty. EPSS 0.3% chance of exploitation in the next 30 days.
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.
Severity
CVSS 3.1
6.5 mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N- EPSS
- 0.3% chance of exploitation in the next 30 days; higher than 20% of CVEs (scores of 2026-11-01)
- CWE
- CWE-444
- Published
- Modified
- Record from
- the NVD, synced
Affected
- netty:netty
References
- https://github.com/netty/netty
- https://github.com/netty/netty/blob/netty-4.1.137.Final/codec-http/src/main/java/io/netty/handler/codec/http/HttpObjectDecoder.java#L866
- https://github.com/netty/netty/commit/640d4d3324f7b811a4903d0730c8ccb35500500c
- https://github.com/netty/netty/commit/ca87393b0e9e13c493d213a268e727a6d44e1585
- https://github.com/netty/netty/releases/tag/netty-4.1.138.Final