CVE-2025-9784
Undertow MadeYouReset HTTP/2 DDoS Vulnerability
7.5
HIGH
CVSS 3.1
EPSS 2.2%
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).
How to fix CVE-2025-9784
To remediate CVE-2025-9784, upgrade the affected package to a fixed version below.
- —upgrade to 2.3.20-1 or later
- —upgrade to 2.2.38.Final or later
Is CVE-2025-9784 being exploited?
Low — EPSS is 2.2%, meaning exploitation activity has not been observed at scale.
Affected packages (2)
- from 0, < 2.3.20-1
- from 0, < 2.2.38.Final
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | HIGH7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |