Vulnerability record/PUBLISHED/Published Mar 27, 2026 16:13:05 UTC

CVE-2026-28367

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.

Base score8.7/ 10

SeverityHighCVSS 3.1

Exploitability / impact

CVSS metric breakdown

Vector-derived attributes

Base severityHigh

Attack vectorNetworkAV

Attack complexityHighAC

Privileges requiredNonePR

User interactionNoneUI

ScopeChangedS

Confidentiality impactHighC

Integrity impactHighI

Availability impactNoneA

CVSS vector stringCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N

CVSS communicates standardized severity and impact characteristics. It does not establish whether a system is exploitable in your specific environment.

Record context

CVE Numbering Authorityredhat

Last updatedNov 2, 2026 15:45:53 UTC

PublishedMar 27, 2026 16:13:05 UTC

ReservedFeb 27, 2026 04:42:16 UTC