High
Undertow: undertow madeyoureset http/2 ddos vulnerability
Type: advisorySources: OSV
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).
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2025-9784
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 2 Nov 2026, 19:24 UTC · Revision 1
Source evidence
Undertow: undertow madeyoureset http/2 ddos vulnerability
core-osv · Original sourcePublished 2 Sept 2025, 13:37 UTC
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).
osv:CVE-2025-9784
Complete source record
{
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"url": "https://osv.dev/vulnerability/CVE-2025-9784",
"method": "structured",
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"title": "Undertow: undertow madeyoureset http/2 ddos vulnerability",
"summary": "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).",
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"modified": "2026-10-28T02:30:22.877890216Z",
"provider": "osv",
"references": [
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