Executive Summary

Undertow servers with the learning‑push handler enabled but maxAge left at its default value of –1 are vulnerable to exploitation via normal HTTP requests. Attackers who can reach the server can trigger the flaw, potentially leading to denial‑of‑service or other adverse effects until the configuration is corrected. The issue is not yet listed in CISA KEV.

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Authoritative CVE Metadata - CVSS Base Score: 5.3 (MEDIUM) - Published: 2024-07-08T22:15:02.527 - Last Modified: 2026-09-08T23:17:20.767

Original Description: A vulnerability was found in Undertow. This issue requires enabling the learning-push handler in the server's config, which is disabled by default, leaving the maxAge config in the handler unconfigured. The default is -1, which makes the handler vulnerable. If someone overwrites that config, the server is not subject to the attack. The attacker needs to be able to reach the server with a normal HTTP request.

"You only lose what you cling to."

— Buddha