What’s Vulnerable › Vulnerabilities

CVE-2019-20444

• Severity: critical (CVSS 9.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 8.9% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2020-01-29 · updated 2026-10-08
• Weakness: CWE-444

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."

Affected products

• Canonical Ubuntu Linux: 18.04
• Debian Linux: 8.0, 9.0, 10.0
• Fedoraproject Fedora: 33
• netty: before 4.1.44 — fixed in 4.1.44
• RedHat Jboss Amq Clients: 2
• Red Hat JBoss EAP: 7.2, 7.3

How to fix

Upgrade to a fixed version: netty 4.1.44. Check the vendor advisory for mitigations.

References

• https://access.redhat.com/errata/RHSA-2020:0497
• https://access.redhat.com/errata/RHSA-2020:0567
• https://access.redhat.com/errata/RHSA-2020:0601
• https://access.redhat.com/errata/RHSA-2020:0605
• https://access.redhat.com/errata/RHSA-2020:0606
• https://access.redhat.com/errata/RHSA-2020:0804
• https://access.redhat.com/errata/RHSA-2020:0805
• https://access.redhat.com/errata/RHSA-2020:0806
• https://access.redhat.com/errata/RHSA-2020:0811
• https://github.com/netty/netty/compare/netty-4.1.43.Final...netty-4.1.44.Final
• https://github.com/netty/netty/issues/9866
• https://github.com/poc-effectiveness/PoCAdaptation/tree/main/Adapted/CVE-2019-20444/5.0.0.Alpha1/exploit

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