CVE-2025-9784

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).

Weakness

The product does not release or incorrectly releases a resource before it is made available for re-use.

Potential Mitigations

• Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
• For example, languages such as Java, Ruby, and Lisp perform automatic garbage collection that releases memory for objects that have been deallocated.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/125.html
• https://cwe.mitre.org/data/definitions/130.html
• https://cwe.mitre.org/data/definitions/131.html
• https://cwe.mitre.org/data/definitions/494.html
• https://cwe.mitre.org/data/definitions/495.html
• https://cwe.mitre.org/data/definitions/496.html
• https://cwe.mitre.org/data/definitions/666.html

References

• https://access.redhat.com/security/cve/CVE-2025-9784
• https://bugzilla.redhat.com/show_bug.cgi?id=2392306