Resource exhaustion in Nodejs Undici

CVE-2026-9675

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 valid…

Vulnerability class: DoS (Denial of Service)

EPSS: 0.004 (35.0th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-9675?
CVE-2026-9675 is a high-severity vulnerability in Nodejs Undici, classified under Uncontrolled Resource Consumption. CVSS score: 7.5/10. Published 2026-06-17.
How severe is CVE-2026-9675?
High severity. CVSS v3 base score is 7.5 out of 10.