CVE-2026-28367
High
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.
SeverityHigh
CVSS8.7
Exploit probability—
Product
Redhat Undertow
PublishedMar 27, 2026
First seenMar 27, 2026
Weakness typeCWE-444CWE-444
How to fix
Update
- io.undertow:undertow-core2.3.25.Final, 2.2.40.Final or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| redhat undertow | No range specified | — |
| redhat build_of_apache_camel_-_hawtio | 4.0 | — |
| redhat build_of_apache_camel_for_spring_boot | 4.0 | — |
| redhat data_grid | 8.0 | — |
| redhat fuse | 7.0.0 | — |
| redhat jboss_enterprise_application_platform | 7.0.0, 8.0.0 | — |
| redhat jboss_enterprise_application_platform_expansion_pack | No range specified | — |
| redhat process_automation | 7.0 | — |
| redhat single_sign-on | 7.0 | — |
| io.undertow:undertow-parentMaven | v ≤ 2.3.23.Final | — |
| io.undertow:undertow-coreMaven | 2.3.0.Final ≤ v < 2.3.25.Final, v < 2.2.40.Final | 2.3.25.Final, 2.2.40.Final |
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