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Vulnerability record · CVE-2019-20444 · published 29 January 2020

CVE-2019-20444: Netty http request smuggling vulnerability

Netty · Netty

HttpObjectDecoder.java in Netty before 4.1.44 allows an HTTP header that lacks a colon, which might be interpreted as a separate header with an incorrect syntax, or might be interpreted as an "invalid fold."

9.1 CVSS 3.1 Critical EPSS 8.9% · top 4.9% CWE-444 · HTTP request smuggling
9.1CVSS 3.1 base score, v2 6.4
8.9%EPSS exploitation probability, 30 days
NoNot in CISA KEV
6Affected product versions listed by NVD
133References, 2 tagged exploit
17 Jun 2026Last modified by NVD

Description

HttpObjectDecoder.java in Netty before 4.1.44 allows an HTTP header that lacks a colon, which might be interpreted as a separate header with an incorrect syntax, or might be interpreted as an "invalid fold."

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Affected products

6 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://access.redhat.com/errata/RHSA-2020:0497 Third Party Advisory
https://access.redhat.com/errata/RHSA-2020:0567 Third Party Advisory
https://access.redhat.com/errata/RHSA-2020:0601 Third Party Advisory
https://access.redhat.com/errata/RHSA-2020:0605 Third Party Advisory
https://access.redhat.com/errata/RHSA-2020:0606 Third Party Advisory
https://access.redhat.com/errata/RHSA-2020:0804 Third Party Advisory
https://access.redhat.com/errata/RHSA-2020:0805 Third Party Advisory
https://access.redhat.com/errata/RHSA-2020:0806 Third Party Advisory
https://access.redhat.com/errata/RHSA-2020:0811 Third Party Advisory
https://github.com/netty/netty/compare/netty-4.1.43.Final...netty-4.1.44.Final PatchThird Party Advisory
https://github.com/netty/netty/issues/9866 ExploitIssue TrackingPatchThird Party Advisory
https://github.com/poc-effectiveness/PoCAdaptation/tree/main/Adapted/CVE-2019-20444/5.0.0.Alpha1/exploit
https://lists.apache.org/thread.html/r059b042bca47be53ff8a51fd04d95eb01bb683f1afa209db136e8cb7@%3Cdev.zookeeper.apache.o
https://lists.apache.org/thread.html/r0aa8b28e76ec01c697b15e161e6797e88fc8d406ed762e253401106e@%3Ccommits.camel.apache.o
https://lists.apache.org/thread.html/r0c3d49bfdbc62fd3915676433cc5899c5506d06da1c552ef1b7923a5@%3Ccommon-issues.hadoop.a
https://lists.apache.org/thread.html/r0f5e72d5f69b4720dfe64fcbc2da9afae949ed1e9cbffa84bb7d92d7@%3Cnotifications.zookeepe
https://lists.apache.org/thread.html/r1b103833cb5bc8466e24ff0ecc5e75b45a705334ab6a444e64e840a0@%3Cissues.bookkeeper.apac
https://lists.apache.org/thread.html/r1fcccf8bdb3531c28bc9aa605a6a1bea7e68cef6fc12e01faafb2fb5@%3Cissues.zookeeper.apach
https://lists.apache.org/thread.html/r205937c85817a911b0c72655c2377e7a2c9322d6ef6ce1b118d34d8d@%3Cdev.geode.apache.org%3
https://lists.apache.org/thread.html/r2f2989b7815d809ff3fda8ce330f553e5f133505afd04ffbc135f35f@%3Cissues.spark.apache.or
https://lists.apache.org/thread.html/r310d2ce22304d5298ff87f10134f918c87919b452734f9841d95682d@%3Ccommits.zookeeper.apac
https://lists.apache.org/thread.html/r34912a9b1a5c269a77b8be94ef6fb6d1e9b3c69129719dc00f01cf0b@%3Cdev.zookeeper.apache.o
https://lists.apache.org/thread.html/r36fcf538b28f2029e8b4f6b9a772f3b107913a78f09b095c5b153a62@%3Cissues.zookeeper.apach
https://lists.apache.org/thread.html/r489886fe72a98768eed665474cba13bad8d6fe0654f24987706636c5@%3Cdev.zookeeper.apache.o
https://lists.apache.org/thread.html/r4c675b2d0cc2a5e506b11ee10d60a378859ee340aca052e4c7ef4749@%3Cnotifications.zookeepe
https://lists.apache.org/thread.html/r4d3f1d3e333d9c2b2f6e6ae8ed8750d4de03410ac294bcd12c7eefa3@%3Ccommits.cassandra.apac
https://lists.apache.org/thread.html/r640eb9b3213058a963e18291f903fc1584e577f60035f941e32f760a@%3Cissues.zookeeper.apach
https://lists.apache.org/thread.html/r6945f3c346b7af89bbd3526a7c9b705b1e3569070ebcd0964bcedd7d@%3Cissues.zookeeper.apach
https://lists.apache.org/thread.html/r70b1ff22ee80e8101805b9a473116dd33265709007d2deb6f8c80bf2@%3Ccommits.druid.apache.o
https://lists.apache.org/thread.html/r7790b9d99696d9eddce8a8c96f13bb68460984294ea6fea3800143e4@%3Ccommits.pulsar.apache.
https://lists.apache.org/thread.html/r804895eedd72c9ec67898286eb185e04df852b0dd5fe53cf5b6138f9@%3Cissues.zookeeper.apach
https://lists.apache.org/thread.html/r819aaeb9944bdcfca438dcc51f05650dc728daf64dfd7d774fc2499b@%3Ccommits.zookeeper.apac
https://lists.apache.org/thread.html/r832724df393a7ef25ca4c7c2eb83ad2d6c21c74569acda5233f9f1ec@%3Ccommits.pulsar.apache.
https://lists.apache.org/thread.html/r8402d67fdfe9cf169f859d52a7670b28a08eff31e54b522cc1432532@%3Ccommon-issues.hadoop.a
https://lists.apache.org/thread.html/r86befa74c5cd1482c711134104aec339bf7ae879f2c4437d7ec477d4@%3Ccommon-commits.hadoop.
https://lists.apache.org/thread.html/r90030b0117490caed526e57271bf4d7f9b012091ac5083c895d16543@%3Ccommon-issues.hadoop.a
https://lists.apache.org/thread.html/r91e0fa345c86c128b75a4a791b4b503b53173ff4c13049ac7129d319@%3Cnotifications.zookeepe
https://lists.apache.org/thread.html/r959474dcf7f88565ed89f6252ca5a274419006cb71348f14764b183d@%3Ccommits.cassandra.apac
https://lists.apache.org/thread.html/r96e08f929234e8ba1ef4a93a0fd2870f535a1f9ab628fabc46115986@%3Cdev.zookeeper.apache.o
https://lists.apache.org/thread.html/r9b20cdac704cf9a583400350e2d5b576fa8417c18ddb961201676c60@%3Ccommits.zookeeper.apac

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Source: NIST National Vulnerability Database (record CVE-2019-20444), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.