Description
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.
Affected products
redhat: build of apache camel - hawtio; redhat: build of apache camel for spring boot; redhat: data grid; redhat: fuse; redhat: jboss enterprise application platform; redhat: jboss enterprise application platform expansion pack; redhat: process automation; redhat: single sign-on; redhat: undertow; redhat: enterprise linux
References4
- access.redhat.com/security/cve/CVE-2026-28369 Vendor Advisory
- bugzilla.redhat.com/show_bug.cgi?id=2443262 Issue TrackingVendor Advisory
- access.redhat.com/errata/RHSA-2026:25125
- access.redhat.com/errata/RHSA-2026:25126
Metrics
- CVSS 3.1
-
9.1
CRITICAL
Score source: NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N - EPSS — exploit probability
- 1% percentile: 53 · as of 12 November 2026
- CWE
- CWE-444
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.