HIGH7.5
GHSA-95h4-w6j8-2rp8
Undertow MadeYouReset HTTP/2 DDoS Vulnerability
Quick fix
GHSA-95h4-w6j8-2rp8 — io.undertow:undertow-core: upgrade to the fixed version with the command below.
# pom.xml: bump <version>2.2.38.Final</version> for io.undertow:undertow-coreDetails
A flaw was found in Undertow where malformed client requests can trigger server-side stream resets without triggering abuse counters. This issue, referred to as the "MadeYouReset" attack, allows malicious clients to induce excessive server workload by repeatedly causing server-side stream aborts. While not a protocol bug, this highlights a common implementation weakness that can be exploited to cause a denial of service (DoS).
Are you affected?
Enter the version of the package you're using.
Affected packages
Maven/io.undertow:undertow-core
Introduced in:
0Fixed in: 2.2.38.FinalFix
# pom.xml: bump <version>2.2.38.Final</version> for io.undertow:undertow-coreMaven/io.undertow:undertow-core
Introduced in:
2.3.0.Alpha1Fixed in: 2.3.20.FinalFix
# pom.xml: bump <version>2.3.20.Final</version> for io.undertow:undertow-coreReferences
- https://nvd.nist.gov/vuln/detail/CVE-2025-9784[ADVISORY]
- https://github.com/undertow-io/undertow/pull/1805[WEB]
- https://github.com/undertow-io/undertow/pull/1804[WEB]
- https://github.com/undertow-io/undertow/pull/1803[WEB]
- https://github.com/undertow-io/undertow/pull/1802[WEB]
- https://github.com/undertow-io/undertow/pull/1778[WEB]
- https://www.kb.cert.org/vuls/id/767506[WEB]
- https://kb.cert.org/vuls/id/767506[WEB]
- https://issues.redhat.com/browse/UNDERTOW-2598[WEB]
- https://github.com/undertow-io/undertow/releases/tag/2.2.38.Final[WEB]
- https://github.com/undertow-io/undertow[PACKAGE]
- https://bugzilla.redhat.com/show_bug.cgi?id=2392306[WEB]
- https://access.redhat.com/security/cve/CVE-2025-9784[WEB]
- https://access.redhat.com/errata/RHSA-2026:4924[WEB]
- https://access.redhat.com/errata/RHSA-2026:4917[WEB]
- https://access.redhat.com/errata/RHSA-2026:4916[WEB]
- https://access.redhat.com/errata/RHSA-2026:4915[WEB]
- https://access.redhat.com/errata/RHSA-2026:3892[WEB]
- https://access.redhat.com/errata/RHSA-2026:3891[WEB]
- https://access.redhat.com/errata/RHSA-2026:3889[WEB]
- https://access.redhat.com/errata/RHSA-2026:33372[WEB]
- https://access.redhat.com/errata/RHSA-2026:33371[WEB]
- https://access.redhat.com/errata/RHSA-2026:0386[WEB]
- https://access.redhat.com/errata/RHSA-2026:0384[WEB]
- https://access.redhat.com/errata/RHSA-2026:0383[WEB]
- https://access.redhat.com/errata/RHSA-2025:23143[WEB]