Is CVE-2026-5680 being exploited?

No public exploit is currently tracked.

How severe is CVE-2026-5680?

CVE-2026-5680 has a CVSS v3 severity of HIGH (7.5).

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CVE-2026-5680

Description

A flaw was found in Undertow. A remote attacker could exploit this vulnerability by sending specially crafted WebSocket messages with permessage-deflate negotiated. This could lead to excessive memory consumption due to the PerMessageDeflateFunction.largerBuffer() method using exponential doubling, resulting in a Denial of Service (DoS) for the affected application.