CVE-2026-28367

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

Published: Mar 27, 2026Updated: Sep 21, 2026 Sources: CVE List NVDCWE-444

8.7HIGH

Description

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.

No summary for this CVE yet.

CVSS Vector Breakdown

Exploitability

AV:NAttack Vector

Network

AC:HAttack Complexity

High

PR:NPrivileges Required

None

UI:NUser Interaction

None

Scope

S:CScope

Changed

Impact

C:HConfidentiality

High

I:HIntegrity

High

A:NAvailability

None

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Weaknesses

CWE-444

Affected Products

Red Hat

commercial·USaka redhat

Red Hat JBoss Enterprise Application Platform 8.1.7.GAOn-prem

Operating Systems / linux-distro

Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 8On-prem

Operating Systems / linux-distro

Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 9On-prem

Operating Systems / linux-distro

Red Hat build of Apache Camel for Spring Boot 4LibraryLibrary

OSS Libraries / generic-library

Red Hat build of Apache Camel - HawtIO 4LibraryLibrary

OSS Libraries / generic-library

Red Hat Data Grid 8On-premDatabase

Databases / cache-message-queue

Red Hat Enterprise Linux 10On-premOS

Operating Systems / linux-distro

Red Hat Fuse 7On-premDev Tool

DevTools & CI / ci-cd

and 16 more affected products View all →

Exploitability

Official Patch Available

Workaround Available

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Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

1 technique

Collection

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References

https://access.redhat.com/errata/RHSA-2026:25125

access.redhat.com

https://access.redhat.com/errata/RHSA-2026:25126

access.redhat.com

https://access.redhat.com/security/cve/CVE-2026-28367

access.redhat.com

and 1 more references View all →

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