cvedb.io
CVE-2026-9675
HIGH · CVSS 7.5
EPSS exploitation probability: 0%
Published 2026-06-17T17:17:28.183 · Last modified 2026-06-25T17:46:52.130

Summary

Impact: The undici WebSocket client enforces maxPayloadSize per-frame but does not enforce the cumulative size of fragmented uncompressed messages. A malicious WebSocket server can stream many small fragments that each pass per-frame validation but collectively exceed the configured limit, causing unbounded memory growth in the client process. The result is memory exhaustion and a denial of service. Affected applications are those using the undici WebSocket client (new WebSocket(...)) that can be induced to connect to an attacker-controlled or compromised WebSocket endpoint. This is a regression specific to undici 8.1.0. The 6.25.0 line shipped the equivalent cumulative check from the start and is unaffected. The 7.x line never had the maxPayloadSize feature and is also unaffected. Patc

Affected products

nodejs — undici

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.