High

Undertow: undertow: request smuggling via `\r\r\r` as a header block terminator

Type: advisorySource: Official CVE List1 source record

A flaw was found in Undertow. A remote attacker can exploit this vulnerability by sending `\r\r\r` as a header block terminator. This can be used for request smuggling with certain proxy servers, such as older versions of Apache Traffic Server and Google Cloud Classic Application Load Balancer, potentially leading to unauthorized access or manipulation of web requests.

Announced 27 Mar 2026Source revision 1

Original source ↗

CVE-2026-28367

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-28367

Red Hat JBoss Enterprise Application Platform 8.1.6

Source reference: /containers/cna/affected/0/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 8

Source reference: /containers/cna/affected/1/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 8

Source reference: /containers/cna/affected/2/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 8

Source reference: /containers/cna/affected/3/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 8

Source reference: /containers/cna/affected/4/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 9

Source reference: /containers/cna/affected/5/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 9

Source reference: /containers/cna/affected/6/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 9

Source reference: /containers/cna/affected/7/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 9

Source reference: /containers/cna/affected/8/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat build of Apache Camel for Spring Boot 4

Source reference: /containers/cna/affected/9/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat build of Apache Camel - HawtIO 4

Source reference: /containers/cna/affected/10/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat Data Grid 8

Source reference: /containers/cna/affected/11/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat Enterprise Linux 10

Source reference: /containers/cna/affected/12/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat Enterprise Linux 8

Source reference: /containers/cna/affected/13/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat Enterprise Linux 8

Source reference: /containers/cna/affected/14/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat Enterprise Linux 9

Source reference: /containers/cna/affected/15/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat Fuse 7

Source reference: /containers/cna/affected/16/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat JBoss Enterprise Application Platform 7

Source reference: /containers/cna/affected/17/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat JBoss Enterprise Application Platform 8

Source reference: /containers/cna/affected/18/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat JBoss Enterprise Application Platform 8

Source reference: /containers/cna/affected/19/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat JBoss Enterprise Application Platform Expansion Pack

Source reference: /containers/cna/affected/20/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat JBoss Enterprise Application Platform Expansion Pack

Source reference: /containers/cna/affected/21/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat JBoss Enterprise Application Platform Expansion Pack

Source reference: /containers/cna/affected/22/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat Process Automation 7

Source reference: /containers/cna/affected/23/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Red Hat Single Sign-On 7

Source reference: /containers/cna/affected/24/product

Affected versions: Not stated in this record
Fixed versions: Not stated in this record
Prerequisites: Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "cpes": [
      "cpe:/a:redhat:jboss_enterprise_application_platform:8.1::el9"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat JBoss Enterprise Application Platform 8.1.6",
    "versions": [
      {
        "status": "unaffected",
        "version": "2.3.24.SP2-redhat-00001",
        "lessThan": "*",
        "versionType": "rpm"
      }
    ],
    "packageName": "io.undertow/undertow-core",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:jboss_enterprise_application_platform:8.1::el8",
      "cpe:/a:redhat:jboss_enterprise_application_platform:8.1::el9"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 8",
    "versions": [
      {
        "status": "unaffected",
        "version": "0:2.40.0-7.redhat_00015.1.el8eap",
        "lessThan": "*",
        "versionType": "rpm"
      }
    ],
    "packageName": "eap8-activemq-artemis",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:jboss_enterprise_application_platform:8.1::el8",
      "cpe:/a:redhat:jboss_enterprise_application_platform:8.1::el9"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 8",
    "versions": [
      {
        "status": "unaffected",
        "version": "0:801.6.1-1.GA_redhat_00001.1.el8eap",
        "lessThan": "*",
        "versionType": "rpm"
      }
    ],
    "packageName": "eap8-eap-product-conf-parent",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:jboss_enterprise_application_platform:8.1::el8",
      "cpe:/a:redhat:jboss_enterprise_application_platform:8.1::el9"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 8",
    "versions": [
      {
        "status": "unaffected",
        "version": "0:2.3.24-3.SP2_redhat_00001.1.el8eap",
        "lessThan": "*",
        "versionType": "rpm"
      }
    ],
    "packageName": "eap8-undertow",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:jboss_enterprise_application_platform:8.1::el8",
      "cpe:/a:redhat:jboss_enterprise_application_platform:8.1::el9"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 8",
    "versions": [
      {
        "status": "unaffected",
        "version": "0:8.1.6-7.GA_redhat_00010.1.el8eap",
        "lessThan": "*",
        "versionType": "rpm"
      }
    ],
    "packageName": "eap8-wildfly",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:jboss_enterprise_application_platform:8.1::el8",
      "cpe:/a:redhat:jboss_enterprise_application_platform:8.1::el9"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 9",
    "versions": [
      {
        "status": "unaffected",
        "version": "0:2.40.0-7.redhat_00015.1.el9eap",
        "lessThan": "*",
        "versionType": "rpm"
      }
    ],
    "packageName": "eap8-activemq-artemis",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:jboss_enterprise_application_platform:8.1::el8",
      "cpe:/a:redhat:jboss_enterprise_application_platform:8.1::el9"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 9",
    "versions": [
      {
        "status": "unaffected",
        "version": "0:801.6.1-1.GA_redhat_00001.1.el9eap",
        "lessThan": "*",
        "versionType": "rpm"
      }
    ],
    "packageName": "eap8-eap-product-conf-parent",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:jboss_enterprise_application_platform:8.1::el8",
      "cpe:/a:redhat:jboss_enterprise_application_platform:8.1::el9"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 9",
    "versions": [
      {
        "status": "unaffected",
        "version": "0:2.3.24-3.SP2_redhat_00001.1.el9eap",
        "lessThan": "*",
        "versionType": "rpm"
      }
    ],
    "packageName": "eap8-undertow",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:jboss_enterprise_application_platform:8.1::el8",
      "cpe:/a:redhat:jboss_enterprise_application_platform:8.1::el9"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 9",
    "versions": [
      {
        "status": "unaffected",
        "version": "0:8.1.6-7.GA_redhat_00010.1.el9eap",
        "lessThan": "*",
        "versionType": "rpm"
      }
    ],
    "packageName": "eap8-wildfly",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:camel_spring_boot:4"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat build of Apache Camel for Spring Boot 4",
    "packageName": "undertow-core",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:apache_camel_hawtio:4"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat build of Apache Camel - HawtIO 4",
    "packageName": "undertow-core",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "unaffected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:jboss_data_grid:8"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat Data Grid 8",
    "packageName": "undertow-core",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/o:redhat:enterprise_linux:10"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat Enterprise Linux 10",
    "packageName": "moditect",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "unaffected"
  },
  {
    "cpes": [
      "cpe:/o:redhat:enterprise_linux:8"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat Enterprise Linux 8",
    "packageName": "pki-core:10.6/resteasy",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "unaffected"
  },
  {
    "cpes": [
      "cpe:/o:redhat:enterprise_linux:8"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat Enterprise Linux 8",
    "packageName": "pki-deps:10.6/resteasy",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "unaffected"
  },
  {
    "cpes": [
      "cpe:/o:redhat:enterprise_linux:9"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat Enterprise Linux 9",
    "packageName": "resteasy",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "unaffected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:jboss_fuse:7"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat Fuse 7",
    "packageName": "undertow-core",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:jboss_enterprise_application_platform:7"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat JBoss Enterprise Application Platform 7",
    "packageName": "undertow-core",
    "collectionURL": "https://access.redhat.com/jbossnetwork/restricted/listSoftware.html",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:jboss_enterprise_application_platform:8"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat JBoss Enterprise Application Platform 8",
    "packageName": "org.jberet-jberet-parent",
    "collectionURL": "https://access.redhat.com/jbossnetwork/restricted/listSoftware.html",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:jboss_enterprise_application_platform:8"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat JBoss Enterprise Application Platform 8",
    "packageName": "undertow-core",
    "collectionURL": "https://access.redhat.com/jbossnetwork/restricted/listSoftware.html",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:jbosseapxp"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat JBoss Enterprise Application Platform Expansion Pack",
    "packageName": "org.jberet-jberet-parent",
    "collectionURL": "https://access.redhat.com/jbossnetwork/restricted/listSoftware.html",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:jbosseapxp"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat JBoss Enterprise Application Platform Expansion Pack",
    "packageName": "org.jboss.eap-jboss-eap-xp",
    "collectionURL": "https://access.redhat.com/jbossnetwork/restricted/listSoftware.html",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:jbosseapxp"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat JBoss Enterprise Application Platform Expansion Pack",
    "packageName": "undertow-core",
    "collectionURL": "https://access.redhat.com/jbossnetwork/restricted/listSoftware.html",
    "defaultStatus": "unaffected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:jboss_enterprise_bpms_platform:7"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat Process Automation 7",
    "packageName": "undertow-core",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "affected"
  },
  {
    "cpes": [
      "cpe:/a:redhat:red_hat_single_sign_on:7"
    ],
    "vendor": "Red Hat",
    "product": "Red Hat Single Sign-On 7",
    "packageName": "undertow-core",
    "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
    "defaultStatus": "affected"
  }
]

Related CVEs: CVE-2026-28367
Source reference: /cveMetadata/cveId

Publisher severity

high

Source reference: /containers/cna/metrics

Event: #22271 · Revision 1
Added to Heist Feed: Sun, 25 Oct 2026 05:59:26 GMT
Publisher date: Fri, 27 Mar 2026 16:13:05 GMT

Read the original announcement