GitHub Advisoryadvisory · Maven
GHSA-vqqj-9cmv-hx43 Undertow is Vulnerable to HTTP Request/Response Smuggling
HIGH
Official page ↗
- Aliases
- CVE-2026-28369
- 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. 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.
Related
Alias · CVE (1)
- CVE-2026-28369 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-2026-28369 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-2026-28369 web
- https://bugzilla.redhat.com/show_bug.cgi?id=2443262 web
- https://github.com/undertow-io/undertow package