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).
Fix
Public exploits 1
- drackyjr/CVE-2025-9784 PoC on GitHub
Each line links to the index that lists it, never to exploit code. Exploit-DB's "verified" and a Metasploit rank of good or better count as verified; a PoC-in-GitHub entry is a repository's claim.
Patch, vendor advisory and mitigation references on NVD 1
- https://access.redhat.com/security/cve/CVE-2025-9784 Vendor Advisory
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 1
- First seenCVSS 7.5 · redhatNVD modified 2026-10-14 17:17
Affected (CPE criteria) 10
cpe:2.3:a:redhat:build_of_apache_camel_for_spring_boot:-:*:*:*:*:*:*:*cpe:2.3:a:redhat:fuse:7.0.0:*:*:*:*:*:*:*cpe:2.3:a:redhat:jboss_enterprise_application_platform:7.0.0:*:*:*:*:*:*:*cpe:2.3:a:redhat:jboss_enterprise_application_platform:8.0.0:*:*:*:*:*:*:*cpe:2.3:a:redhat:jboss_enterprise_application_platform_expansion_pack:-:*:*:*:*:*:*:*cpe:2.3:a:redhat:process_automation:7.0:*:*:*:*:*:*:*cpe:2.3:a:redhat:single_sign-on:7.0:*:*:*:*:*:*:*cpe:2.3:a:redhat:undertow:-:*:*:*:*:*:*:*cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:-:*:*:*cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*
References 25
- https://access.redhat.com/errata/RHSA-2025:23143
- https://access.redhat.com/errata/RHSA-2026:0383
- https://access.redhat.com/errata/RHSA-2026:0384
- https://access.redhat.com/errata/RHSA-2026:0386
- https://access.redhat.com/errata/RHSA-2026:33371
- https://access.redhat.com/errata/RHSA-2026:33372
- https://access.redhat.com/errata/RHSA-2026:3889
- https://access.redhat.com/errata/RHSA-2026:3891
- https://access.redhat.com/errata/RHSA-2026:3892
- https://access.redhat.com/errata/RHSA-2026:4915
- https://access.redhat.com/errata/RHSA-2026:4916
- https://access.redhat.com/errata/RHSA-2026:4917
- https://access.redhat.com/errata/RHSA-2026:4924
- https://access.redhat.com/errata/RHSA-2026:76128
- https://access.redhat.com/errata/RHSA-2026:76129
- https://access.redhat.com/errata/RHSA-2026:76130
- https://access.redhat.com/errata/RHSA-2026:76132
- https://access.redhat.com/errata/RHSA-2026:76134
- https://access.redhat.com/security/cve/CVE-2025-9784 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2392306 Issue Tracking
- https://github.com/undertow-io/undertow/pull/1778
- https://github.com/undertow-io/undertow/releases/tag/2.2.38.Final
- https://issues.redhat.com/browse/UNDERTOW-2598
- https://kb.cert.org/vuls/id/767506
- https://www.kb.cert.org/vuls/id/767506