PT-2025-35569 · Undertow · Undertow

Osidb Bzimport · Published 2025-09-02 · Updated 2026-03-19 · CVE-2025-9784

Positive Technologies (AI Summary)

CVSS v3.1

7.5

High

Base vector

AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Name of the Vulnerable Software and Affected Versions Undertow (affected versions not specified)

Description A flaw exists in Undertow where malformed client requests can trigger server-side stream resets without triggering abuse counters. This issue, known as the “MadeYouReset” attack, allows malicious clients to induce excessive server workload by repeatedly causing server-side stream aborts, potentially leading to a denial of service (DoS).

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

DoS

Allocation of Resources Without Limits

Resource Exhaustion

Improper Resource Release

Weakness Enumeration

CWE-770

CWE-400

CWE-404

Related Identifiers

CVE-2025-9784

GHSA-95H4-W6J8-2RP8

RHSA-2026:0383

RHSA-2026:0384

RHSA-2026:3889

RHSA-2026:3891

RHSA-2026:4915

RHSA-2026:4916

RHSA-2026:4917

Affected Products

Undertow

References · 40

• https://access.redhat.com/errata/RHSA-2026:4924 · Vendor Advisory
• https://cve.org/CVERecord?id=CVE-2025-9784 · Security Note
• https://access.redhat.com/errata/RHSA-2026:3892 · Vendor Advisory
• https://access.redhat.com/errata/RHSA-2026:0384 · Vendor Advisory
• https://access.redhat.com/errata/RHSA-2026:4916 · Vendor Advisory
• https://access.redhat.com/errata/RHSA-2026:3891 · Vendor Advisory
• https://ubuntu.com/security/CVE-2025-9784 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2025-9784 · Security Note
• https://access.redhat.com/errata/RHSA-2026:4917 · Vendor Advisory
• https://access.redhat.com/errata/RHSA-2025:23143 · Vendor Advisory
• https://osv.dev/vulnerability/CVE-2025-9784 · Vendor Advisory
• https://osv.dev/vulnerability/DEBIAN-CVE-2025-9784 · Vendor Advisory
• https://security-tracker.debian.org/tracker/CVE-2025-9784 · Vendor Advisory
• https://access.redhat.com/errata/RHSA-2026:0383 · Vendor Advisory
• https://access.redhat.com/errata/RHSA-2026:4915 · Vendor Advisory