GitHub Advisoryadvisory · Maven
GHSA-3gv6-g396-9v4r Undertow is Vulnerable to HTTP Request/Response Smuggling
HIGH
Official page ↗
- Aliases
- CVE-2026-28367
- Ecosystem
- Maven
- Packages
- io.undertow:undertow-parent
- Severity
- High
- CVSS vector
- CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N
- Weaknesses
- CWE-444
- Reviewed
- 2026-03-31
Affected packages
• Maven io.undertow:undertow-parent: <= 2.3.23.Final (no fix yet)
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.
Related
Alias · CVE (1)
- CVE-2026-28367 A flaw was found in Undertow. vulnerability
Weakness · CWE (1)
- CWE-444 Inconsistent Interpretation of HTTP Requests weakness
References
- https://nvd.nist.gov/vuln/detail/CVE-2026-28367 advisory
- https://access.redhat.com/errata/RHSA-2026:25125 web
- https://access.redhat.com/errata/RHSA-2026:25126 web
- https://access.redhat.com/security/cve/CVE-2026-28367 web
- https://bugzilla.redhat.com/show_bug.cgi?id=2443260 web
- https://github.com/undertow-io/undertow package