undertow: A flaw was found in Undertow where malformed client requests can trigger server-side stream resets without triggering...
CVE-2025-9784 is fixed in undertow on 1 platform by DEBIAN-CVE-2025-9784 (version 2.3.20-1), released September 2, 2025. It is not reported as exploited. Patch Radar priority: High.
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).
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Linux | |||
| undertow · Debian 14 | 2.3.20-1 | DEBIAN-CVE-2025-9784 | Sep 2, 2025 |
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