Review reviewCritical

CVE-2026-28367

Red Hat Red Hat JBoss Enterprise Application Platform 8.1, Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 8, Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 9

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.

CVSS: 9.1
EPSS: 0.71%
CISA KEV: Not listed
Published: 2026.03.28

PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability0.71%

Technical severityCVSS 9.1

Vulnerability overview

Affected product and versions

Product: Red Hat Red Hat JBoss Enterprise Application Platform 8.1, Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 8, Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 9
Affected versions: 4.0, 8.0, 7.0.0, 8.0.0, 7.0
Fixed versions: No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

1
Identify
Confirm that Red Hat Red Hat JBoss Enterprise Application Platform 8.1, Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 8, Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 9 and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CWE: CWE-444