GHSA-3gv6-g396-9v4r
Undertow is Vulnerable to HTTP Request/Response Smuggling
Packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| Maven | io.undertow:undertow-core | >= 2.3.0.Final, < 2.3.25.Final | 2.3.25.Final |
| Maven | io.undertow:undertow-core | < 2.2.40.Final | 2.2.40.Final |
Details
As written in the advisory (Markdown source, shown as plain text).
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.
References
External links from the advisory. They lead to third-party sites.
- https://nvd.nist.gov/vuln/detail/CVE-2026-28367
- https://github.com/undertow-io/undertow/commit/3ece0bf2b2cf5e01db8ca25e41b831e66d3f5961
- https://github.com/undertow-io/undertow/commit/904e26f1be62fb00b440538608a9574839821878
- https://github.com/undertow-io/undertow/commit/c5dc41479e9c3576552d7e98e31bb1c237ae155e
- https://access.redhat.com/errata/RHSA-2026:25125
- https://access.redhat.com/errata/RHSA-2026:25126
- https://access.redhat.com/security/cve/CVE-2026-28367
- https://bugzilla.redhat.com/show_bug.cgi?id=2443260
- https://github.com/undertow-io/undertow