Allocation of Resources Without Limits or Throttling Affecting undertow package, versions <2.3.20-1


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
2.33% (82nd percentile)

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  • Snyk IDSNYK-DEBIANUNSTABLE-UNDERTOW-12484654
  • published4 Sept 2025
  • disclosed2 Sept 2025

Introduced: 2 Sep 2025

CVE-2025-9784  (opens in a new tab)
CWE-770  (opens in a new tab)

How to fix?

Upgrade Debian:unstable undertow to version 2.3.20-1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream undertow package and not the undertow package as distributed by Debian. See How to fix? for Debian:unstable relevant fixed versions and status.

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 Base Scores

version 3.1