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Vulnerability · Published Sep 2, 2025 · Assigned by redhat

CVE-2025-9784Undertow: undertow madeyoureset http/2 ddos vulnerability

High 7.5

In plain English

A high-severity resource allocation without limits in undertow. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 2.3% (higher than 84% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.5High
Exploit odds (30 days)2.3%top 16.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack tooling1Public PoC

Official description

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).

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:14undertow2.3.20-1DEBIAN-CVE-2025-9784
Mavenio.undertow:undertow-core2.3.20.FinalGHSA-95h4-w6j8-2rp8
Mavenio.undertow:undertow-core2.2.38.FinalGHSA-95h4-w6j8-2rp8
Ubuntu:25.10resteasyno fix listedUBUNTU-CVE-2025-9784
Ubuntu:26.04:LTSresteasyno fix listedUBUNTU-CVE-2025-9784
Ubuntu:26.10resteasyno fix listedUBUNTU-CVE-2025-9784
Ubuntu:25.10undertowno fix listedUBUNTU-CVE-2025-9784
Ubuntu:26.04:LTSundertowno fix listedUBUNTU-CVE-2025-9784
Ubuntu:26.10undertowno fix listedUBUNTU-CVE-2025-9784

Affected products (as reported)

VendorProductVersions
undertow 0 – before 2.2.38.Final
Red Hat Red Hat build of Apache Camel 4.14.2 for Spring Boot 3.5.8 see references
Red Hat Red Hat JBoss Enterprise Application Platform 7.1 EUS for RHEL 7 see references
Red Hat Red Hat JBoss Enterprise Application Platform 7.3 EUS for RHEL 7 see references
Red Hat Red Hat JBoss Enterprise Application Platform 7.4.24 see references
Red Hat Red Hat JBoss Enterprise Application Platform 7.4 ELS on RHEL 7 see references
Red Hat Red Hat JBoss Enterprise Application Platform 7.4 ELS on RHEL 7 see references
Red Hat Red Hat JBoss Enterprise Application Platform 7.4 ELS on RHEL 8 see references
Red Hat Red Hat JBoss Enterprise Application Platform 7.4 ELS on RHEL 8 see references
Red Hat Red Hat JBoss Enterprise Application Platform 7.4 ELS on RHEL 9 see references
Red Hat Red Hat JBoss Enterprise Application Platform 7.4 ELS on RHEL 9 see references
Red Hat Red Hat JBoss Enterprise Application Platform 8.0 see references
Red Hat Red Hat JBoss Enterprise Application Platform 8.0 for RHEL 8 see references
Red Hat Red Hat JBoss Enterprise Application Platform 8.0 for RHEL 8 see references
Red Hat Red Hat JBoss Enterprise Application Platform 8.0 for RHEL 8 see references
Red Hat Red Hat JBoss Enterprise Application Platform 8.0 for RHEL 8 see references
Red Hat Red Hat JBoss Enterprise Application Platform 8.0 for RHEL 8 see references
Red Hat Red Hat JBoss Enterprise Application Platform 8.0 for RHEL 8 see references
Red Hat Red Hat JBoss Enterprise Application Platform 8.0 for RHEL 9 see references
Red Hat Red Hat JBoss Enterprise Application Platform 8.0 for RHEL 9 see references
Red Hat Red Hat JBoss Enterprise Application Platform 8.0 for RHEL 9 see references
Red Hat Red Hat JBoss Enterprise Application Platform 8.0 for RHEL 9 see references
Red Hat Red Hat JBoss Enterprise Application Platform 8.0 for RHEL 9 see references
Red Hat Red Hat JBoss Enterprise Application Platform 8.0 for RHEL 9 see references
Red Hat Red Hat JBoss Enterprise Application Platform 8.1.3 see references
Red Hat Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 8 see references
Red Hat Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 8 see references
Red Hat Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 8 see references
Red Hat Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 8 see references
Red Hat Red Hat JBoss Enterprise Application Platform 8.1 for RHEL 8 see references

Weakness: CWE-770, CWE-404 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References