HTTP fails to validate against control chars in header names which may lead to HTTP request smuggling

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Summary

CVECVE-2021-43797
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2021-12-09 19:15:07 UTC
Updated2026-10-08 22:17:12 UTC
DescriptionNetty is an asynchronous event-driven network application framework for rapid development of maintainable high performance protocol servers & clients. Netty prior to version 4.1.71.Final skips control chars when they are present at the beginning / end of the header name. It should instead fail fast as these are not allowed by the spec and could lead to HTTP request smuggling. Failing to do the validation might cause netty to "sanitize" header names before it forward these to another remote system when used as proxy. This remote system can't see the invalid usage anymore, and therefore does not do the validation itself. Users should upgrade to version 4.1.71.Final.

Risk And Classification

Primary CVSS: v3.1 6.5 MEDIUM from [email protected]

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

EPSS: 0.028840000 probability, percentile 0.866820000 (date 2026-10-20)

Problem Types: CWE-444 | CWE-444 CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request Smuggling')

VersionSourceTypeScoreSeverityVector
3.1[email protected]Primary6.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
3.1[email protected]Secondary6.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
3.1CNADECLARED6.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
2.0[email protected]Primary4.3AV:N/AC:M/Au:N/C:N/I:P/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

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

CVSS v2.0 Breakdown

Access Vector
Network
Access Complexity
Medium
Authentication
None
Confidentiality
None
Integrity
Partial
Availability
None

AV:N/AC:M/Au:N/C:N/I:P/A:N

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Debian Debian Linux 10.0 All All All
Operating System Debian Debian Linux 11.0 All All All
Application Netapp Oncommand Workflow Automation - All All All
Application Netapp Snapcenter - All All All
Application Netty Netty All All All All
Application Oracle Banking Deposits And Lines Of Credit Servicing 2.7 All All All
Application Oracle Banking Party Management 2.7.0 All All All
Application Oracle Banking Platform 2.6.2 All All All
Application Oracle Coherence 12.2.1.4.0 All All All
Application Oracle Coherence 14.1.1.0.0 All All All
Application Oracle Communications Cloud Native Core Binding Support Function 1.11.0 All All All
Application Oracle Communications Cloud Native Core Network Slice Selection Function 1.8.0 All All All
Application Oracle Communications Cloud Native Core Policy 1.15.0 All All All
Application Oracle Communications Cloud Native Core Security Edge Protection Proxy 1.7.0 All All All
Application Oracle Communications Cloud Native Core Unified Data Repository 1.15.0 All All All
Application Oracle Communications Design Studio 7.4.2 All All All
Application Oracle Communications Instant Messaging Server 8.1 All All All
Application Oracle Helidon 1.4.10 All All All
Application Oracle Helidon 2.4.0 All All All
Application Oracle Peoplesoft Enterprise Peopletools 8.58 All All All
Application Oracle Peoplesoft Enterprise Peopletools 8.59 All All All
Application Quarkus Quarkus All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Netty Netty affected <= 4.1.7.0.Final Not specified

References

ReferenceSourceLinkTags
HTTP fails to validate against control chars in header names which may lead to HTTP request smuggling · Advisory · netty/netty · GitHub af854a3a-2127-422b-91ae-364da2661108 github.com Third Party Advisory
Oracle Critical Patch Update Advisory - April 2022 af854a3a-2127-422b-91ae-364da2661108 www.oracle.com Patch, Third Party Advisory
Merge pull request from GHSA-wx5j-54mm-rqqq · netty/netty@07aa6b5 · GitHub af854a3a-2127-422b-91ae-364da2661108 github.com Patch, Third Party Advisory
[SECURITY] [DLA 3268-1] netty security update af854a3a-2127-422b-91ae-364da2661108 lists.debian.org Mailing List, Third Party Advisory
Debian -- Security Information -- DSA-5316-1 netty af854a3a-2127-422b-91ae-364da2661108 www.debian.org Third Party Advisory
Oracle Critical Patch Update Advisory - July 2022 af854a3a-2127-422b-91ae-364da2661108 www.oracle.com Patch, Third Party Advisory
CVE-2021-43797 Apache Netty Vulnerability in NetApp Products | NetApp Product Security af854a3a-2127-422b-91ae-364da2661108 security.netapp.com Third Party Advisory
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Legacy QID Mappings

  • 181469 Debian Security Update for netty (DLA 3268-1)
  • 181471 Debian Security Update for netty (DSA 5316-1)
  • 183061 Debian Security Update for netty (CVE-2021-43797)
  • 199574 Ubuntu Security Notification for Netty Vulnerabilities (USN-6049-1)
  • 240458 Red Hat Update for JBoss Enterprise Application Platform 7.4.5 on RHEL 7 (RHSA-2022:4918)
  • 240459 Red Hat Update for JBoss Enterprise Application Platform 7.4.5 on RHEL 8 (RHSA-2022:4919)
  • 240566 Red Hat Update for Satellite 6.11 Release (RHSA-2022:5498)
  • 376547 Oracle PeopleSoft Enterprise PeopleTools Product Multiple Vulnerabilities (CPUAPR2022)
  • 376549 Oracle Coherence April 2022 Critical Patch Update (CPUAPR2022)
  • 753182 SUSE Enterprise Linux Security Update for netty3 (SUSE-SU-2022:2047-1)
  • 960505 Rocky Linux Security Update for Satellite (RLSA-2022:5498)

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