CVE-2019-20444

CVE-2019-20444 is a critical-severity vulnerability in Netty with a CVSS 3.x base score of 9.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-444.

Key facts

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."

Frequently asked questions

What is CVE-2019-20444?
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."
How severe is CVE-2019-20444?
CVE-2019-20444 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2019-20444 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 9% (95th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-20444?
CVE-2019-20444 primarily affects Netty. In total, 9 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2019-20444?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2019-20444 published?
CVE-2019-20444 was published on 2020-01-29 and last updated on 2026-06-17.

References

Affected products (9)

More vulnerabilities in Netty

All CVEs affecting Netty →

Other CWE-444 (HTTP Request/Response Smuggling) vulnerabilities

Browse all CWE-444 (HTTP Request/Response Smuggling) vulnerabilities →