CVE-2025-9784
Published: 02 September 2025
Summary
CVE-2025-9784 is a high-severity Allocation of Resources Without Limits or Throttling (CWE-770) vulnerability in Redhat Jboss Enterprise Application Platform. Its CVSS base score is 7.5 (High).
Operationally, ranked in the top 15.1% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
Deeper analysis
A flaw was found in Undertow where malformed client requests can trigger server-side stream resets without incrementing abuse counters. This implementation weakness, labeled the "MadeYouReset" attack, enables repeated server-side stream aborts that consume excessive resources and produce a denial of service. The issue is tracked as CVE-2025-9784 with a CVSS 3.1 score of 7.5 and is associated with CWE-770 and CWE-404.
Unauthenticated remote attackers can send crafted HTTP/2 requests to induce the resets. Because the abuse-detection mechanisms are bypassed, an attacker can sustain high volumes of resets, driving up CPU and memory usage on the server until service is disrupted.
Red Hat has published multiple errata (RHSA-2025:23143, RHSA-2026:0383, RHSA-2026:0384, RHSA-2026:0386, and RHSA-2026:3889) that address the vulnerability through updated Undertow packages. The current and peak EPSS scores remain low at 0.0223 with no material increase observed after disclosure.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-26388
Vulnerability details
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…
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aborts. While not a protocol bug, this highlights a common implementation weakness that can be exploited to cause a denial of service (DoS).
- CWE(s)
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Contingency plan updates ensure recovery strategies address unbounded resource allocation, making it harder for attackers to exploit lack of throttling to cause prolonged outages.
Imposes an inactivity-based limit on network resource allocation, throttling the number of concurrently held connections.
This control implements explicit throttling on session allocation, addressing the weakness of allocating resources without limits.
Plan testing exercises resource allocation limits and throttling during simulated failures, directly addressing weaknesses that allow unbounded resource use.
Provides continuity when unbounded resource allocation at the primary site leads to exhaustion and downtime.
Alternate services allow operations to continue when primary allocation of resources lacks limits or throttling.
Explicit planning of security-related actions requires defining limits, windows, and resource allocations, making allocation without throttling far less likely.
Measures of performance include tracking allocation behavior and throttling effectiveness, reducing the window for resource exhaustion attacks.