CVE-2026-28367
Undertow: undertow: request smuggling via `\r\r\r` as a header block terminator
HIGH 8.7
At a glance
- Source
- NVD
- EPSS
- EPSS 0.72 % · percentile 54 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- redhat
- NVD status
- Modified
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.
Weaknesses (CWE)
- CWE-444 — Inconsistent Interpretation of HTTP Requests
References
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | HIGH 8.7 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N | redhat |
| CVSS 3.1 | HIGH 8.7 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N | NVD · secalert@redhat.com (Secondary) |
| CVSS 3.1 | CRITICAL 9.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N | NVD · nvd@nist.gov (Primary) |
Advisories
- GHSA-3gv6-g396-9v4r — Undertow is Vulnerable to HTTP Request/Response Smuggling
European references
- ENISA EUVD · EUVD-2026-16694
- GCVE · GCVE-0-2026-28367
Affected configurations (NVD CPE)
cpe:2.3:a:redhat:build_of_apache_camel_-_hawtio:4.0:*:*:*:*:*:*:*cpe:2.3:a:redhat:build_of_apache_camel_for_spring_boot:4.0:*:*:*:*:*:*:*cpe:2.3:a:redhat:data_grid:8.0:*:*:*:*:*:*:*cpe:2.3:a:redhat:fuse:7.0.0:*:*:*:*:*:*:*cpe:2.3:a:redhat:jboss_enterprise_application_platform:7.0.0:*:*:*:*:*:*:*cpe:2.3:a:redhat:jboss_enterprise_application_platform:8.0.0:*:*:*:*:*:*:*cpe:2.3:a:redhat:jboss_enterprise_application_platform_expansion_pack:-:*:*:*:*:*:*:*cpe:2.3:a:redhat:process_automation:7.0:*:*:*:*:*:*:*cpe:2.3:a:redhat:single_sign-on:7.0:*:*:*:*:*:*:*cpe:2.3:a:redhat:undertow:-:*:*:*:*:*:*:*
Affected products
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |