CVE-2025-9784

CWE-770 — Allocation without LimitsCWE-404CWE-125 — Out-of-bounds Read8 documents6 sources
Severity
7.5HIGH
EPSS
1.6%
top 18.57%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
5
Redhat Enterprise LinuxRedhat FuseRedhat Jboss Enterprise Application Platform+2 more
Timeline
PublishedSep 2
Latest updateSep 4

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).

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HExploitability: 3.9 | Impact: 3.6

Affected Packages6 packages

▶Mavenio.undertow:undertow-core2.3.0.Alpha1 — 2.3.20.Final+1
▶Debianundertow< 2.3.20-1
▶NVDredhat/fuse7.0.0

Also affects: Enterprise Linux 8.0, 9.0

🔴Vulnerability Details

4
OSV
Undertow MadeYouReset HTTP/2 DDoS Vulnerability↗2025-09-02
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OSV
CVE-2025-9784: A flaw was found in Undertow where malformed client requests can trigger server-side stream resets without triggering abuse counters↗2025-09-02
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CVEList
Undertow: undertow madeyoureset http/2 ddos vulnerability↗2025-09-02
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GHSA
Undertow MadeYouReset HTTP/2 DDoS Vulnerability↗2025-09-02
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📋Vendor Advisories

3
Red Hat
kernel: hfsplus: fix slab-out-of-bounds in hfsplus_bnode_read()↗2025-09-04
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Red Hat
undertow: Undertow MadeYouReset HTTP/2 DDoS Vulnerability↗2025-09-01
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Debian
CVE-2025-9784: undertow - A flaw was found in Undertow where malformed client requests can trigger server-...↗2025
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