CVE-2025-9784
High
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).
SeverityHigh
CVSS7.5
Exploit probability—
Product
Redhat Undertow
PublishedSep 2, 2025
First seenSep 2, 2025
Weakness typeCWE-770Allocation of resources without limits
How to fix
Update
- io.undertow:undertow-core2.2.38.Final, 2.3.20.Final or later
Vendor advisories
- access.redhat.com/security/cve/CVE-2025-9784
- access.redhat.com/errata/RHSA-2025:23143
- access.redhat.com/errata/RHSA-2026:0383
- access.redhat.com/errata/RHSA-2026:0384
- access.redhat.com/errata/RHSA-2026:0386
- access.redhat.com/errata/RHSA-2026:33371
- access.redhat.com/errata/RHSA-2026:33372
- access.redhat.com/errata/RHSA-2026:3889
- access.redhat.com/errata/RHSA-2026:3891
- access.redhat.com/errata/RHSA-2026:3892
- access.redhat.com/errata/RHSA-2026:4915
- access.redhat.com/errata/RHSA-2026:4916
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| redhat undertow | No range specified | — |
| redhat build_of_apache_camel_for_spring_boot | No range specified | — |
| redhat fuse | 7.0.0 | — |
| redhat jboss_enterprise_application_platform | 7.0.0, 8.0.0 | — |
| redhat jboss_enterprise_application_platform_expansion_pack | No range specified | — |
| redhat process_automation | 7.0 | — |
| redhat single_sign-on | 7.0 | — |
| redhat enterprise_linux | 8.0, 9.0 | — |
| io.undertow:undertow-coreMaven | v < 2.2.38.Final, 2.3.0.Alpha1 ≤ v < 2.3.20.Final | 2.2.38.Final, 2.3.20.Final |
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