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
Unknown · Unknown
9.1CriticalCVSS 3.1
Recommended action
Within 72 hours
Critical technical impact with a remotely reachable, unauthenticated path and a public exploit reference; no CISA KEV confirmation is currently recorded.
Published severityCritical→Operational priority:Critical, unchanged from published severity.unchanged
Evidence used
No CISA KEV confirmation is currently recorded.
A structured source references public exploit or proof-of-concept material.
The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
EPSS is 13.83% for the current model date.
Compensating controls
Validate the affected product branch and deploy the verified fixed release.
Restrict the affected network interface to trusted sources where business-safe.
Increase monitoring for the attack path and post-exploitation behaviour described in the report.
Verification
Confirm that the asset runs Unknown Unknown and falls inside the recorded affected range.
Verify the installed build against the product-specific fixed version after deployment.
Validate exposure, authentication requirements and compensating controls in the actual environment.
Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Distribution package intelligence
Release-specific package status
Debian findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.
4 package states
Repository candidate not checked
A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.
Distribution release
Source package
Vendor state
Fixed version
Evidence
Debian trixietrixie · source
netty
Vendor fix publishedDebian records a fixed source-package version for this release.
These OSV and GitHub advisory ranges apply only to the named package and ecosystem. A listed fixed version is not a universal product patch or proof that an update is installed.
Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.
1 current
CVE-2019-20445 · CSAF 2.0 · revision 3 · finalRed Hat Product Securitynetty: HttpObjectDecoder.java allows Content-Length header to accompanied by second Content-Length header
10 known affected
The vendor explicitly identifies these products as affected by this CVE.
netty as a component of Red Hat JBoss A-MQ 6
netty as a component of Red Hat JBoss Enterprise Application Platform 5
netty as a component of Red Hat JBoss Enterprise Application Platform 6
netty as a component of Red Hat JBoss Fuse 6
netty as a component of Red Hat JBoss Operations Network 3
openshift3/ose-logging-elasticsearch5 as a component of Red Hat OpenShift Container Platform 3.11
openshift4/ose-logging-elasticsearch5 as a component of Red Hat OpenShift Container Platform 4
candlepin as a component of Red Hat Satellite 6
candlepin-selinux as a component of Red Hat Satellite 6
candlepin.src as a component of Red Hat Satellite 6
Summary
A flaw was found in Netty before version 4.1.44, where it accepted multiple Content-Length headers and also accepted both Transfer-Encoding, as well as Content-Length headers where it should reject the message under such circumstances. In circumstances where Netty is used in the context of a server, it could result in a viable HTTP smuggling vulnerability.
Remediation
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
Optional official sources
National CERT insights ?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.
Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.
Official European source
ENISA European Vulnerability Database
Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.
1 current
ENISA EUVD identifier
EUVD-2020-0308
No EUVD known-exploited evidence
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.
EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
0.0
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 72 hours
Critical technical impact with a remotely reachable, unauthenticated path and a public exploit reference; no CISA KEV confirmation is currently recorded.
Patch available
01
What, why and how
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
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.
Why
The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination.
How
An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
What
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.
Why
The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination.
How
An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
02
Exploit reality and attack path
CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.
Observed exploitation ?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No confirmed evidence
No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.
Public PoC / exploit material ?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.Reference recorded
A structured CVE source labels at least one public reference as exploit material. BlackTree has not independently validated that it is safe, reliable or weaponised.
Likely attack path
a network path → Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness ?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling'). The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination.
CVSS vector ?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.
AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CHighConfidentiality impact: A successful attack can cause a major loss.IHighIntegrity impact: A successful attack can cause a major loss.ANoneAvailability impact: No direct loss is represented by this metric.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
Only matched European and national findings are included. Language selectors and unavailable sources are omitted.
ENISA EUVD · EUVD-2020-0308Official EUVD mapping
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.
Official EUVD record ↗BSI · German · WID-SEC-2025-1459Dell Data Protection Advisor: Mehrere Schwachstellen
Ein Angreifer kann mehrere Schwachstellen in Dell Data Protection Advisor ausnutzen, um beliebigen Programmcode auszuführen, um einen Denial of Service Angriff durchzuführen, und um weitere nicht näher spezifizierte Angriffe durchzuführen.
Official advisory ↗BSI · German · WID-SEC-2024-1926Red Hat JBoss Enterprise Application Platform: Mehrere Schwachstellen
Ein Angreifer kann mehrere Schwachstellen in Red Hat JBoss Enterprise Application Platform auf Red Hat Enterprise Linux ausnutzen, um beliebigen Programmcode auszuführen, einen Denial-of-Service-Zustand zu erzeugen, vertrauliche Informationen preiszugeben, Dateien und Daten zu manipulieren oder Sicherheitsmaßnahmen zu umgehen.
Official advisory ↗BSI · German · WID-SEC-2022-2133JFrog Artifactory: Mehrere Schwachstellen in Drittanbieter-Komponenten
JFrog Artifactory nutzt verschiedene Komponenten von Drittanbietern. Diese enthalten mehrere Schwachstellen. Neuen Informationen von JFrog zufolge sind diese Schwachstellen jedoch nicht in Produkten von JFrog ausnutzbar.
Official advisory ↗CERT-FR · French · CERTFR-2026-AVI-1165Multiples vulnérabilités dans les produits IBM
Official advisory ↗CERT-FR · French · CERTFR-2024-AVI-0031Multiples vulnérabilités dans les produits IBM
/6830983
Bulletin de sécurité IBM 6831007 du 05 janvier 2024
https://www.ibm.com/support/pages/node/6831007
Bulletin de sécurité IBM 6831013 du 05 janvier 2024
https://www.ibm.com/support/pages/node/6831013
Bulletin de sécurité IBM 7062347 du 11 janvier 2024
https://www.ibm.com/support/pages/node/7062347
Bulletin de sécurité IBM 7105500 du 06 janvier 2024
https://www.ibm.com/support/pages/node/7105500
Référence CVE CVE-2018-17196
https://www.cve.org/CVERecord?id=CVE-2018-17196
Référence CVE CVE-2019-16869
https://www.cve.org/CVERecord?id=CVE-2019-16869
Référence CVE CVE-2019-20444
https://www.cve.org/CVERecord?id=CVE-2019-20444
Référence CVE CVE-2019-20445
https://www.cve.org/CVERecord?id=CVE-2019-20445
Référence CVE CVE-2019-9518
https://www.cve.org/CVERecord?id=CVE-2019-9518
Référence CVE CVE-2020-11612
https://www.cve.org/CVERecord?id=CVE-2020-11612
Référence CVE CVE-2020-7238
https://www.cve.org/CVERecord?id=CVE-2020-7238
Référence CVE CVE-2021-21290
https://www.cve.org/CVERecord?id=CVE-2021-21290
Référence CVE CVE-2021-21295
https://www.cve.org/CVERecord?id=CVE-2021-21295
Référence CVE CVE-2021-21409
https://www.cve.org/CVERecord?id=CVE-2021-21409
Référence CVE CVE-2021-25741
https://www.cve.org/CVERecord?id=CVE-2021-25741
Référence CVE CVE-2021-37136
https://www.cve.org/CVERecord?id=CVE-
Official advisory ↗CERT-FR · French · CERTFR-2022-AVI-113Multiples vulnérabilités dans les produits NetApp
De multiples vulnérabilités ont été découvertes dans les produits
NetApp. Elles permettent à un attaquant de provoquer une atteinte à
l'intégrité des données et une atteinte à la confidentialité des
données.
Official advisory ↗JVN iPedia · Japanese · JVNDB-2019-014408Netty における HTTP リクエストスマグリングに関する脆弱性
Operational remediation based on structured source evidence.
Status ?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04
Evidence and provenance
Published 29 Jan 2020 · Last source change 8 Oct 2026, 21:14 UTC · CWE-444 · Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
CVE recordCVE.org · 5.2
CVSS sourceNIST NVD
EPSS source ?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2020-0308
Product sourceVendor CSAF · Red Hat Product Security
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceNIST NVD
NVD statusNVD modified after enrichment
Missing structured fields: affected product. Missing data is not evidence of low risk; review the primary advisory.
Affected versionsThe structured affected or fixed version information changed.
Before
n/a · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
After
n/a · Fixed: Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.