CVE-2026-28367

[CVE catalog]

Severity

High · CVSS 8.7CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N

Published

Jan 1, 2026, 12:00:00 AM UTC

Source

[NVD] · [CVE record]

EPSS

0.72% · Oct 25, 2026

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. undertow: Undertow: Request smuggling via `\r\r\r` as a header block terminator The Undertow web server is susceptible to request smuggling when deployed with certain proxy servers that forward `\r\r\r` as a header block terminator. This flaw could enable an attacker to manipulate web requests, potentially leading to unauthorized access. Red Hat products using Undertow in environments with vulnerable proxy configurations, such as those found in older versions of Apache Traffic Server or Google Cloud Classic Application Load Balancer, are at risk. The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.