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).

The remote Redhat Enterprise Linux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2026:0383 advisory.

    Red Hat JBoss Enterprise Application Platform 8 is a platform for Java applications based on the WildFly     application runtime. This release of Red Hat JBoss  Enterprise Application Platform 8.1.3 serves as a     replacement for Red Hat JBoss Enterprise Application Platform 8.1.2, and includes bug fixes and     enhancements. See the Red Hat JBoss Enterprise Application Platform 8.1.3 Release Notes for information     about the most significant bug fixes and enhancements included in this release.

    Security Fix(es):

    * undertow-core: Undertow HTTP Server Fails to Reject Malformed Host Headers Leading to Potential Cache     Poisoning and SSRF [eap-8.1.z] (CVE-2025-12543)

    * undertow: OutOfMemory when parsing form data encoding with application/x-www-form-urlencoded [eap-8.1.z]     (CVE-2024-3884)

    * undertow-core: Undertow MadeYouReset HTTP/2 DDoS Vulnerability [eap-8.1.z] (CVE-2025-9784)

    For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and     other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Redhat Enterprise Linux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2026:0384 advisory.

    Red Hat JBoss Enterprise Application Platform 8 is a platform for Java applications based on the WildFly     application runtime. This release of Red Hat JBoss  Enterprise Application Platform 8.1.3 serves as a     replacement for Red Hat JBoss Enterprise Application Platform 8.1.2, and includes bug fixes and     enhancements. See the Red Hat JBoss Enterprise Application Platform 8.1.3 Release Notes for information     about the most significant bug fixes and enhancements included in this release.

    Security Fix(es):

    * undertow-core: Undertow HTTP Server Fails to Reject Malformed Host Headers Leading to Potential Cache     Poisoning and SSRF [eap-8.1.z] (CVE-2025-12543)

    * undertow: OutOfMemory when parsing form data encoding with application/x-www-form-urlencoded [eap-8.1.z]     (CVE-2024-3884)

    * undertow-core: Undertow MadeYouReset HTTP/2 DDoS Vulnerability [eap-8.1.z] (CVE-2025-9784)

    For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and     other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - 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). (CVE-2025-9784)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Severity
283525	RHEL 8 : Red Hat JBoss Enterprise Application Platform 8.1.3 (RHSA-2026:0383)	Nessus	Red Hat Local Security Checks	critical
283521	RHEL 9 : Red Hat JBoss Enterprise Application Platform 8.1.3 (RHSA-2026:0384)	Nessus	Red Hat Local Security Checks	critical
261317	Linux Distros Unpatched Vulnerability : CVE-2025-9784	Nessus	Misc.	high

Detections

Analytics

CVE-2025-9784

high

Tenable Plugins

critical

critical

high