CVSS v3
7.5
HIGH
EPSS Score
0.6 %
exploit probability, as of 2026-09-28
CISA KEV
No
known exploited
Exploitation
—
SSVC status
Description
Undertow is a flexible performant web server used in JBoss EAP and WildFly. A flaw was found in how Undertow handles WebSocket connections. Specifically, certain configuration limits like message buffer sizes and session timeouts cannot be adjusted and default to being unlimited. This allows a remote attacker to send large amounts of data or maintain connections indefinitely, potentially crashing the server by exhausting its memory or other resources.
Technical details
- Published
- 2026-08-31
- Last Modified
- 2026-09-01
Frequently asked questions
What is CVE-2026-81624?
Undertow is a flexible performant web server used in JBoss EAP and WildFly. A flaw was found in how Undertow handles WebSocket connections. Specifically, certain configuration limits like message buffer sizes and session timeouts cannot be adjusted and default to being unlimited. This allows a remote attacker to send large amounts of data or maintain connections indefinitely, potentially crashing the server by exhausting its memory or other resources.
Is CVE-2026-81624 actively exploited?
Active exploitation of CVE-2026-81624 has not been confirmed. Its EPSS score was 0.6% on 2026-09-28, the estimated probability of exploitation in the next 30 days.
What is the CVSS score for CVE-2026-81624?
CVE-2026-81624 has a CVSS v3 base score of 7.5 (HIGH severity).
Is CVE-2026-81624 affecting your environment?
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