CVE-2026-28369

Undertow: undertow: request smuggling via malformed http request headers

publishedCWE-444

A flaw was found in Undertow. When Undertow receives an HTTP request where the first header line starts with one or more spaces, it incorrectly processes the request by stripping these leading spaces. This behavior, which violates HTTP standards, can be exploited by a remote attacker to perform request smuggling. Request smuggling allows an attacker to bypass security mechanisms, access restricted information, or manipulate web caches, potentially leading to unauthorized actions or data exposure.

Technical severity8.7 highCVSS 3.1 · CNA: redhat

Published2026-03-27Source updated 2026-11-04

Collected2026-11-053 attributed sources

Fixes and workarounds

No remediation reported in collected sources.

Missing remediation information is not evidence that no patch exists.

Affected products and versions

Affected products, source version ranges and reporting authorities
Product	Versions	Authority
Red Hat JBoss Enterprise Application Platform 8.1.6 Red Hat `io.undertow/undertow-core` https://access.redhat.com/downloads/content/package-browser/	≥ 2.3.24.SP2-redhat-00001; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 8 Red Hat `eap8-activemq-artemis` https://access.redhat.com/downloads/content/package-browser/	≥ 0:2.40.0-7.redhat_00015.1.el8eap; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 8 Red Hat `eap8-eap-product-conf-parent` https://access.redhat.com/downloads/content/package-browser/	≥ 0:801.6.1-1.GA_redhat_00001.1.el8eap; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 8 Red Hat `eap8-undertow` https://access.redhat.com/downloads/content/package-browser/	≥ 0:2.3.24-3.SP2_redhat_00001.1.el8eap; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 8 Red Hat `eap8-wildfly` https://access.redhat.com/downloads/content/package-browser/	≥ 0:8.1.6-7.GA_redhat_00010.1.el8eap; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 9 Red Hat `eap8-activemq-artemis` https://access.redhat.com/downloads/content/package-browser/	≥ 0:2.40.0-7.redhat_00015.1.el9eap; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 9 Red Hat `eap8-eap-product-conf-parent` https://access.redhat.com/downloads/content/package-browser/	≥ 0:801.6.1-1.GA_redhat_00001.1.el9eap; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 9 Red Hat `eap8-undertow` https://access.redhat.com/downloads/content/package-browser/	≥ 0:2.3.24-3.SP2_redhat_00001.1.el9eap; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 9 Red Hat `eap8-wildfly` https://access.redhat.com/downloads/content/package-browser/	≥ 0:8.1.6-7.GA_redhat_00010.1.el9eap; < * (unaffected, rpm) Other versions: affected	CNA: redhat
Red Hat build of Apache Camel for Spring Boot 4 Red Hat `undertow-core` https://access.redhat.com/downloads/content/package-browser/	Range not reported Other versions: affected	CNA: redhat
Red Hat build of Apache Camel - HawtIO 4 Red Hat `undertow-core` https://access.redhat.com/downloads/content/package-browser/	Range not reported Other versions: unaffected	CNA: redhat
Red Hat Data Grid 8 Red Hat `undertow-core` https://access.redhat.com/downloads/content/package-browser/	Range not reported Other versions: affected	CNA: redhat
Red Hat Enterprise Linux 10 Red Hat `moditect` https://access.redhat.com/downloads/content/package-browser/	Range not reported Other versions: unaffected	CNA: redhat
Red Hat Enterprise Linux 8 Red Hat `pki-core:10.6/resteasy` https://access.redhat.com/downloads/content/package-browser/	Range not reported Other versions: unaffected	CNA: redhat
Red Hat Enterprise Linux 8 Red Hat `pki-deps:10.6/resteasy` https://access.redhat.com/downloads/content/package-browser/	Range not reported Other versions: unaffected	CNA: redhat
Red Hat Enterprise Linux 9 Red Hat `resteasy` https://access.redhat.com/downloads/content/package-browser/	Range not reported Other versions: affected	CNA: redhat
Red Hat Fuse 7 Red Hat `undertow-core` https://access.redhat.com/downloads/content/package-browser/	Range not reported Other versions: affected	CNA: redhat
Red Hat JBoss Enterprise Application Platform 7 Red Hat `undertow-core` https://access.redhat.com/jbossnetwork/restricted/listSoftware.html	Range not reported Other versions: affected	CNA: redhat
Red Hat JBoss Enterprise Application Platform 8 Red Hat `org.jberet-jberet-parent` https://access.redhat.com/jbossnetwork/restricted/listSoftware.html	Range not reported Other versions: affected	CNA: redhat
Red Hat JBoss Enterprise Application Platform 8 Red Hat `undertow-core` https://access.redhat.com/jbossnetwork/restricted/listSoftware.html	Range not reported Other versions: affected	CNA: redhat
Red Hat JBoss Enterprise Application Platform Expansion Pack Red Hat `org.jberet-jberet-parent` https://access.redhat.com/jbossnetwork/restricted/listSoftware.html	Range not reported Other versions: affected	CNA: redhat
Red Hat JBoss Enterprise Application Platform Expansion Pack Red Hat `org.jboss.eap-jboss-eap-xp` https://access.redhat.com/jbossnetwork/restricted/listSoftware.html	Range not reported Other versions: affected	CNA: redhat
Red Hat JBoss Enterprise Application Platform Expansion Pack Red Hat `undertow-core` https://access.redhat.com/jbossnetwork/restricted/listSoftware.html	Range not reported Other versions: unaffected	CNA: redhat
Red Hat Process Automation 7 Red Hat `undertow-core` https://access.redhat.com/downloads/content/package-browser/	Range not reported Other versions: affected	CNA: redhat
Red Hat Single Sign-On 7 Red Hat `undertow-core` https://access.redhat.com/downloads/content/package-browser/	Range not reported Other versions: affected	CNA: redhat

Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.

NVD applicability configurations (1)

These expressions retain AND/OR operators, negation, and required environmental products. A listed product is not sufficient to establish exposure when additional conditions apply.

[
  {
    "negate": false,
    "nodes": [
      {
        "cpeMatch": [
          {
            "criteria": "cpe:2.3:a:redhat:build_of_apache_camel_-_hawtio:4.0:*:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:a:redhat:build_of_apache_camel_for_spring_boot:4.0:*:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:a:redhat:data_grid:8.0:*:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:a:redhat:fuse:7.0.0:*:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:a:redhat:jboss_enterprise_application_platform:7.0.0:*:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:a:redhat:jboss_enterprise_application_platform:8.0.0:*:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:a:redhat:jboss_enterprise_application_platform_expansion_pack:-:*:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:a:redhat:process_automation:7.0:*:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:a:redhat:single_sign-on:7.0:*:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:a:redhat:undertow:-:*:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*",
            "vulnerable": true
          }
        ],
        "negate": false,
        "operator": "OR"
      }
    ],
    "operator": "OR"
  }
]

CVSS assessments

CVSS scores, vectors and reporting authorities
Version / score	Vector	Authority
3.1 / 8.7 high	`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N`	CNA: redhat
3.1 / 9.1 critical	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N`	NVD: [email protected]
3.1 / 8.7 high	`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N`	NVD: [email protected]

Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

References

https://access.redhat.com/errata/RHSA-2026:25125CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:25126CNA: redhat · vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/security/cve/CVE-2026-28369CNA: redhat · vdb-entry, x_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2443262CNA: redhat · issue-tracking, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:25125[email protected]
https://access.redhat.com/errata/RHSA-2026:25126[email protected]
https://access.redhat.com/security/cve/CVE-2026-28369[email protected] · Vendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2443262[email protected] · Issue Tracking, Vendor Advisory

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