CVE-2026-28368

Undertow: undertow: request smuggling via inconsistent header parsing

8.7 HighFix available

A flaw was found in Undertow. This vulnerability allows a remote attacker to construct specially crafted requests where header names are parsed differently by Undertow compared to upstream proxies. This discrepancy in header interpretation can be exploited to launch request smuggling attacks, potentially bypassing security controls and accessing unauthorized resources.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: High
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: High
Integrity: High
Availability: None

Exploit likelihood

0.73%Up 0.6 points since Mar 28, 2026

What each source reports

CVE List Score used 8.7

Undertow: undertow: request smuggling via inconsistent header parsing

Record: CVE-2026-28368
CVSS 3.1: 8.7 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N
Weakness: CWE-444
Updated: 2026-11-04

EUVDEUVD-2026-16696 8.7

Record: EUVD-2026-16696
CVSS 3.1: 8.7 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N
Updated: 2026-11-04

GitHub AdvisoriesGHSA-8v4x-mgvp-p658 8.7

Undertow is Vulnerable to HTTP Request/Response Smuggling

Record: GHSA-8v4x-mgvp-p658
CVSS 3.1: 8.7 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N
Weakness: CWE-444
Updated: 2026-11-04

NVD 8.7

Record: CVE-2026-28368
CVSS 3.1: 8.7 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N
CVSS 3.1: 9.1 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Weakness: CWE-444
Updated: 2026-11-05

OSVDEBIAN-CVE-2026-28368 9.1

Record: DEBIAN-CVE-2026-28368
CVSS 3.1: 9.1 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Updated: 2026-11-05

OSVGHSA-8v4x-mgvp-p658 8.7

Undertow is Vulnerable to HTTP Request/Response Smuggling

Record: GHSA-8v4x-mgvp-p658
CVSS 3.1: 8.7 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N
Weakness: CWE-444
Updated: 2026-11-04

OSVRHSA-2026:25125 8.7

Red Hat Security Advisory: Red Hat JBoss Enterprise Application Platform 8.1.6 security update

Record: RHSA-2026:25125
CVSS 3.1: 8.7 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N
Updated: 2026-11-02

OSVUBUNTU-CVE-2026-28368 8.7

Record: UBUNTU-CVE-2026-28368
CVSS 3.1: 8.7 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N
CVSS 3.1: 9.1 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Updated: 2026-11-02

Affected products

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Affected packages

Affected packages
Package	Affected	Fixed
`io.undertow:undertow-core` Maven	before 2.2.40.Final	2.2.40.Final
`io.undertow:undertow-core` Maven	2.3.0.Final up to 2.3.25.Final	2.3.25.Final
`undertow` Debian:14	All versions, plus listed versions 1.3.11-11.3.16-11.3.19-11.3.21-11.3.23-1 Show 45 moreShow less 1.3.4-11.3.5-11.3.7-11.4.0-11.4.1-11.4.18-11.4.20-11.4.21-11.4.21-21.4.22-11.4.23-11.4.23-21.4.23-31.4.25-11.4.25-21.4.3-11.4.4-11.4.6-11.4.7-11.4.8-12.0.23-12.0.25-12.0.26-12.0.27-12.0.28-12.0.29-12.0.30-12.1.0-12.1.1-12.1.3-12.2.0-12.2.10-12.2.12-12.2.13-12.2.14-12.2.16-12.2.17-12.2.18-12.2.19-12.2.2-12.2.20-12.2.21-12.2.3-12.2.4-12.2.5-1	None known
`io.undertow:undertow-core` Maven	before 2.2.40.Final, plus listed versions 1.0.0.Alpha11.0.0.Alpha101.0.0.Alpha111.0.0.Alpha121.0.0.Alpha13 Show 45 moreShow less 1.0.0.Alpha141.0.0.Alpha151.0.0.Alpha161.0.0.Alpha171.0.0.Alpha181.0.0.Alpha191.0.0.Alpha21.0.0.Alpha201.0.0.Alpha211.0.0.Alpha221.0.0.Alpha31.0.0.Alpha41.0.0.Alpha51.0.0.Alpha61.0.0.Alpha71.0.0.Alpha81.0.0.Alpha91.0.0.Beta11.0.0.Beta101.0.0.Beta111.0.0.Beta121.0.0.Beta131.0.0.Beta141.0.0.Beta151.0.0.Beta161.0.0.Beta171.0.0.Beta181.0.0.Beta191.0.0.Beta21.0.0.Beta201.0.0.Beta211.0.0.Beta221.0.0.Beta231.0.0.Beta241.0.0.Beta251.0.0.Beta261.0.0.Beta271.0.0.Beta281.0.0.Beta291.0.0.Beta31.0.0.Beta301.0.0.Beta311.0.0.Beta321.0.0.Beta331.0.0.Beta4	2.2.40.Final
`io.undertow:undertow-core` Maven	2.3.0.Final up to 2.3.25.Final, plus listed versions 2.3.1.Final2.3.10.Final2.3.11.Final2.3.12.Final2.3.13.Final Show 19 moreShow less 2.3.14.Final2.3.15.Final2.3.16.Final2.3.17.Final2.3.18.Final2.3.19.Final2.3.2.Final2.3.20.Final2.3.21.Final2.3.22.Final2.3.23.Final2.3.24.Final2.3.3.Final2.3.4.Final2.3.5.Final2.3.6.Final2.3.7.Final2.3.8.Final2.3.9.Final	2.3.25.Final
`eap8-activemq-artemis` Red Hat:jboss_enterprise_application_platform:8.1::el8 From an advisory covering 4 CVEs	before 0:2.40.0-7.redhat_00015.1.el8eap	0:2.40.0-7.redhat_00015.1.el8eap
`eap8-activemq-artemis-cli` Red Hat:jboss_enterprise_application_platform:8.1::el8 From an advisory covering 4 CVEs	before 0:2.40.0-7.redhat_00015.1.el8eap	0:2.40.0-7.redhat_00015.1.el8eap
`eap8-activemq-artemis-commons` Red Hat:jboss_enterprise_application_platform:8.1::el8 From an advisory covering 4 CVEs	before 0:2.40.0-7.redhat_00015.1.el8eap	0:2.40.0-7.redhat_00015.1.el8eap
`eap8-activemq-artemis-core-client` Red Hat:jboss_enterprise_application_platform:8.1::el8 From an advisory covering 4 CVEs	before 0:2.40.0-7.redhat_00015.1.el8eap	0:2.40.0-7.redhat_00015.1.el8eap
`eap8-activemq-artemis-dto` Red Hat:jboss_enterprise_application_platform:8.1::el8 From an advisory covering 4 CVEs	before 0:2.40.0-7.redhat_00015.1.el8eap	0:2.40.0-7.redhat_00015.1.el8eap

Show 47 moreShow less

History

History
Recorded	Changed	Sources
Nov 6, 2026	affected	CVE List, EUVD, NVD, OSV
Nov 4, 2026	affected, facts, references	GitHub Advisories, OSV
Nov 2, 2026	first indexed	CVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-28368 is a high vulnerability (CVSS 8.7) in Redhat Undertow, published March 27, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.73%, the 54th percentile. Fixed in io.undertow:undertow-core 2.2.40.Final.

References

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This page doesn't list everything

Left out here: 264 versions. The JSON record has them.

Package	Affected	Fixed
`eap8-activemq-artemis-hornetq-protocol` Red Hat:jboss_enterprise_application_platform:8.1::el8 From an advisory covering 4 CVEs	before 0:2.40.0-7.redhat_00015.1.el8eap	0:2.40.0-7.redhat_00015.1.el8eap
`eap8-activemq-artemis-hqclient-protocol` Red Hat:jboss_enterprise_application_platform:8.1::el8 From an advisory covering 4 CVEs	before 0:2.40.0-7.redhat_00015.1.el8eap	0:2.40.0-7.redhat_00015.1.el8eap
`eap8-activemq-artemis-jakarta-client` Red Hat:jboss_enterprise_application_platform:8.1::el8 From an advisory covering 4 CVEs	before 0:2.40.0-7.redhat_00015.1.el8eap	0:2.40.0-7.redhat_00015.1.el8eap
`eap8-activemq-artemis-jakarta-ra` Red Hat:jboss_enterprise_application_platform:8.1::el8 From an advisory covering 4 CVEs	before 0:2.40.0-7.redhat_00015.1.el8eap	0:2.40.0-7.redhat_00015.1.el8eap
`eap8-activemq-artemis-jakarta-server` Red Hat:jboss_enterprise_application_platform:8.1::el8 From an advisory covering 4 CVEs	before 0:2.40.0-7.redhat_00015.1.el8eap	0:2.40.0-7.redhat_00015.1.el8eap
`eap8-activemq-artemis-jakarta-service-extensions` Red Hat:jboss_enterprise_application_platform:8.1::el8 From an advisory covering 4 CVEs	before 0:2.40.0-7.redhat_00015.1.el8eap	0:2.40.0-7.redhat_00015.1.el8eap
`eap8-activemq-artemis-jdbc-store` Red Hat:jboss_enterprise_application_platform:8.1::el8 From an advisory covering 4 CVEs	before 0:2.40.0-7.redhat_00015.1.el8eap	0:2.40.0-7.redhat_00015.1.el8eap
`eap8-activemq-artemis-journal` Red Hat:jboss_enterprise_application_platform:8.1::el8 From an advisory covering 4 CVEs	before 0:2.40.0-7.redhat_00015.1.el8eap	0:2.40.0-7.redhat_00015.1.el8eap
`eap8-activemq-artemis-selector` Red Hat:jboss_enterprise_application_platform:8.1::el8 From an advisory covering 4 CVEs	before 0:2.40.0-7.redhat_00015.1.el8eap	0:2.40.0-7.redhat_00015.1.el8eap
`eap8-activemq-artemis-server` Red Hat:jboss_enterprise_application_platform:8.1::el8 From an advisory covering 4 CVEs	before 0:2.40.0-7.redhat_00015.1.el8eap	0:2.40.0-7.redhat_00015.1.el8eap
`eap8-eap-product-conf-parent` Red Hat:jboss_enterprise_application_platform:8.1::el8 From an advisory covering 4 CVEs	before 0:801.6.1-1.GA_redhat_00001.1.el8eap	0:801.6.1-1.GA_redhat_00001.1.el8eap
`eap8-eap-product-conf-wildfly-ee-feature-pack` Red Hat:jboss_enterprise_application_platform:8.1::el8 From an advisory covering 4 CVEs	before 0:801.6.1-1.GA_redhat_00001.1.el8eap	0:801.6.1-1.GA_redhat_00001.1.el8eap
`eap8-undertow` Red Hat:jboss_enterprise_application_platform:8.1::el8 From an advisory covering 4 CVEs	before 0:2.3.24-3.SP2_redhat_00001.1.el8eap	0:2.3.24-3.SP2_redhat_00001.1.el8eap
`eap8-wildfly` Red Hat:jboss_enterprise_application_platform:8.1::el8 From an advisory covering 4 CVEs	before 0:8.1.6-7.GA_redhat_00010.1.el8eap	0:8.1.6-7.GA_redhat_00010.1.el8eap
`eap8-wildfly-java-jdk17` Red Hat:jboss_enterprise_application_platform:8.1::el8 From an advisory covering 4 CVEs	before 0:8.1.6-7.GA_redhat_00010.1.el8eap	0:8.1.6-7.GA_redhat_00010.1.el8eap
`eap8-wildfly-java-jdk21` Red Hat:jboss_enterprise_application_platform:8.1::el8 From an advisory covering 4 CVEs	before 0:8.1.6-7.GA_redhat_00010.1.el8eap	0:8.1.6-7.GA_redhat_00010.1.el8eap
`eap8-wildfly-modules` Red Hat:jboss_enterprise_application_platform:8.1::el8 From an advisory covering 4 CVEs	before 0:8.1.6-7.GA_redhat_00010.1.el8eap	0:8.1.6-7.GA_redhat_00010.1.el8eap
`eap8-activemq-artemis` Red Hat:jboss_enterprise_application_platform:8.1::el9 From an advisory covering 4 CVEs	before 0:2.40.0-7.redhat_00015.1.el9eap	0:2.40.0-7.redhat_00015.1.el9eap
`eap8-activemq-artemis-cli` Red Hat:jboss_enterprise_application_platform:8.1::el9 From an advisory covering 4 CVEs	before 0:2.40.0-7.redhat_00015.1.el9eap	0:2.40.0-7.redhat_00015.1.el9eap
`eap8-activemq-artemis-commons` Red Hat:jboss_enterprise_application_platform:8.1::el9 From an advisory covering 4 CVEs	before 0:2.40.0-7.redhat_00015.1.el9eap	0:2.40.0-7.redhat_00015.1.el9eap
`eap8-activemq-artemis-core-client` Red Hat:jboss_enterprise_application_platform:8.1::el9 From an advisory covering 4 CVEs	before 0:2.40.0-7.redhat_00015.1.el9eap	0:2.40.0-7.redhat_00015.1.el9eap
`eap8-activemq-artemis-dto` Red Hat:jboss_enterprise_application_platform:8.1::el9 From an advisory covering 4 CVEs	before 0:2.40.0-7.redhat_00015.1.el9eap	0:2.40.0-7.redhat_00015.1.el9eap
`eap8-activemq-artemis-hornetq-protocol` Red Hat:jboss_enterprise_application_platform:8.1::el9 From an advisory covering 4 CVEs	before 0:2.40.0-7.redhat_00015.1.el9eap	0:2.40.0-7.redhat_00015.1.el9eap
`eap8-activemq-artemis-hqclient-protocol` Red Hat:jboss_enterprise_application_platform:8.1::el9 From an advisory covering 4 CVEs	before 0:2.40.0-7.redhat_00015.1.el9eap	0:2.40.0-7.redhat_00015.1.el9eap
`eap8-activemq-artemis-jakarta-client` Red Hat:jboss_enterprise_application_platform:8.1::el9 From an advisory covering 4 CVEs	before 0:2.40.0-7.redhat_00015.1.el9eap	0:2.40.0-7.redhat_00015.1.el9eap
`eap8-activemq-artemis-jakarta-ra` Red Hat:jboss_enterprise_application_platform:8.1::el9 From an advisory covering 4 CVEs	before 0:2.40.0-7.redhat_00015.1.el9eap	0:2.40.0-7.redhat_00015.1.el9eap
`eap8-activemq-artemis-jakarta-server` Red Hat:jboss_enterprise_application_platform:8.1::el9 From an advisory covering 4 CVEs	before 0:2.40.0-7.redhat_00015.1.el9eap	0:2.40.0-7.redhat_00015.1.el9eap
`eap8-activemq-artemis-jakarta-service-extensions` Red Hat:jboss_enterprise_application_platform:8.1::el9 From an advisory covering 4 CVEs	before 0:2.40.0-7.redhat_00015.1.el9eap	0:2.40.0-7.redhat_00015.1.el9eap
`eap8-activemq-artemis-jdbc-store` Red Hat:jboss_enterprise_application_platform:8.1::el9 From an advisory covering 4 CVEs	before 0:2.40.0-7.redhat_00015.1.el9eap	0:2.40.0-7.redhat_00015.1.el9eap
`eap8-activemq-artemis-journal` Red Hat:jboss_enterprise_application_platform:8.1::el9 From an advisory covering 4 CVEs	before 0:2.40.0-7.redhat_00015.1.el9eap	0:2.40.0-7.redhat_00015.1.el9eap
`eap8-activemq-artemis-selector` Red Hat:jboss_enterprise_application_platform:8.1::el9 From an advisory covering 4 CVEs	before 0:2.40.0-7.redhat_00015.1.el9eap	0:2.40.0-7.redhat_00015.1.el9eap
`eap8-activemq-artemis-server` Red Hat:jboss_enterprise_application_platform:8.1::el9 From an advisory covering 4 CVEs	before 0:2.40.0-7.redhat_00015.1.el9eap	0:2.40.0-7.redhat_00015.1.el9eap
`eap8-eap-product-conf-parent` Red Hat:jboss_enterprise_application_platform:8.1::el9 From an advisory covering 4 CVEs	before 0:801.6.1-1.GA_redhat_00001.1.el9eap	0:801.6.1-1.GA_redhat_00001.1.el9eap
`eap8-eap-product-conf-wildfly-ee-feature-pack` Red Hat:jboss_enterprise_application_platform:8.1::el9 From an advisory covering 4 CVEs	before 0:801.6.1-1.GA_redhat_00001.1.el9eap	0:801.6.1-1.GA_redhat_00001.1.el9eap
`eap8-undertow` Red Hat:jboss_enterprise_application_platform:8.1::el9 From an advisory covering 4 CVEs	before 0:2.3.24-3.SP2_redhat_00001.1.el9eap	0:2.3.24-3.SP2_redhat_00001.1.el9eap
`eap8-wildfly` Red Hat:jboss_enterprise_application_platform:8.1::el9 From an advisory covering 4 CVEs	before 0:8.1.6-7.GA_redhat_00010.1.el9eap	0:8.1.6-7.GA_redhat_00010.1.el9eap
`eap8-wildfly-java-jdk17` Red Hat:jboss_enterprise_application_platform:8.1::el9 From an advisory covering 4 CVEs	before 0:8.1.6-7.GA_redhat_00010.1.el9eap	0:8.1.6-7.GA_redhat_00010.1.el9eap
`eap8-wildfly-java-jdk21` Red Hat:jboss_enterprise_application_platform:8.1::el9 From an advisory covering 4 CVEs	before 0:8.1.6-7.GA_redhat_00010.1.el9eap	0:8.1.6-7.GA_redhat_00010.1.el9eap
`eap8-wildfly-modules` Red Hat:jboss_enterprise_application_platform:8.1::el9 From an advisory covering 4 CVEs	before 0:8.1.6-7.GA_redhat_00010.1.el9eap	0:8.1.6-7.GA_redhat_00010.1.el9eap
`undertow` Ubuntu:Pro:16.04:LTS	All versions, plus listed versions 1.3.4-11.3.5-11.3.7-11.3.11-11.3.16-11.3.16-1ubuntu0.1~esm1	None known
`undertow` Ubuntu:Pro:18.04:LTS	All versions, plus listed versions 1.4.20-11.4.21-11.4.22-11.4.23-11.4.23-2build11.4.23-31.4.23-3ubuntu0.1~esm1	None known
`undertow` Ubuntu:Pro:20.04:LTS	All versions, plus listed versions 2.0.23-12.0.27-12.0.28-12.0.29-12.0.29-1ubuntu0.1~esm1	None known
`undertow` Ubuntu:Pro:22.04:LTS	All versions, plus listed versions 2.2.8-12.2.12-12.2.13-12.2.14-12.2.16-12.2.16-1ubuntu0.1~esm1	None known
`undertow` Ubuntu:Pro:24.04:LTS	All versions, plus listed versions 2.3.8-22.3.8-2ubuntu0.1~esm1	None known
`undertow` Ubuntu:25.10	All versions, plus listed versions 2.3.18-12.3.18-2	None known
`undertow` Ubuntu:26.10	All versions, plus listed versions 2.3.20-1ubuntu1	None known
`undertow` Ubuntu:26.04:LTS	All versions, plus listed versions 2.3.18-22.3.20-12.3.20-1ubuntu1	None known