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CVE Record

CVE-2019-20444: HttpObjectDecoder.java in Netty before 4.1.44 allows an HTTP header that lacks a colon, which might be inte...

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."

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2019-20444 affects Netty before 4.1.44. It involves unusual HTTP headers without a colon being parsed inconsistently. The public bundle does not provide CVSS, confirmed impact, or active exploitation evidence, so urgency depends on whether vulnerable Netty is used on externally reachable HTTP paths.

Executive priority

Medium operational priority if Netty is present on exposed HTTP services; lower priority for unreachable or unused dependencies. Because impact and exploitation evidence are incomplete in the supplied sources, focus on confirming exposure and upgrading through normal dependency maintenance channels.

Technical view

Netty's HttpObjectDecoder.java before 4.1.44 could treat a colonless HTTP header as a separate malformed header or invalid fold. The available sources point to the 4.1.44.Final change set and downstream dependency updates, but do not include exploit mechanics, CVSS scoring, or a detailed impact chain.

Likely exposure

Most likely exposure is Java software directly or transitively using Netty before 4.1.44 for HTTP parsing. Internet-facing HTTP services deserve priority. Apache Druid and ZooKeeper mailing-list references show downstream projects tracking Netty updates, but local exposure must be verified from each application's dependency graph.

Exploitation context

The source bundle marks KEV as false and provides no cited evidence of active exploitation. Public details describe malformed HTTP header parsing behavior, not weaponized exploitation. Treat this as a dependency and parser-hardening issue unless vendor guidance or internal exposure analysis shows higher risk.

Researcher notes

Key gaps are missing CVSS, CWE, and impact analysis in the supplied bundle. The strongest evidence is the version boundary before 4.1.44 and downstream project references. Avoid assuming request smuggling, denial of service, or active exploitation without additional cited vendor evidence.

Mitigation direction

  • Upgrade Netty to 4.1.44.Final or later where compatible.
  • Update downstream products that bundle vulnerable Netty versions.
  • Check vendor advisories before suppressing scanner findings.
  • Prioritize externally reachable HTTP services using Netty.
  • Document accepted risk if upgrade is deferred.

Validation and detection

  • Inventory direct and transitive Netty versions in builds and containers.
  • Confirm no runtime classpath includes Netty before 4.1.44.
  • Identify whether Netty handles HTTP requests on exposed paths.
  • Review scanner findings against actual deployed artifacts.
  • Retest after dependency or vendor package upgrades.
Prepared
Confidence
medium
Sources
8

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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CVE-2019-20444 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
0Timeline events
0ADP providers
41Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.