CVE-2026-85014 (CVSS 5.9)

Description

undici's experimental WebSocketStream client crashes the whole Node.js process when a remote peer closes the TCP connection without a WebSocket close handshake. On an unclean close the internal socket-close handler calls abort on the writable stream unconditionally and discards the returned promise, but per the WHATWG Streams standard aborting a locked writable returns a promise that rejects with a TypeError. Because the application holds a writer on that writable, which is the only way to write, the rejection is never observed and Node's default unhandled-rejection behavior terminates the process. An untrusted server can therefore crash a client with a single abrupt disconnect, with no authentication and no application mistake. This affects undici versions from 7.0.0 up to 7.29.1 and from 8.0.0 up to 8.10.2. Users should upgrade to undici 7.29.1 or 8.10.2.

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CVSS v3.1 Score

5.9

MEDIUM

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS — Exploit Prediction

0.0037

Probability of exploitation

0.30%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-248 CWE-248

CWE-754 CWE-754

References

Other References

https://cna.openjsf.org/security-advisories.html https://github.com/nodejs/undici/security/advisories/GHSA-rx4f-c7p8-82vq

Frequently Asked Questions

What is CVE-2026-85014? +

undici's experimental WebSocketStream client crashes the whole Node.js process when a remote peer closes the TCP connection without a WebSocket close handshake. On an unclean close the internal socket-close handler calls abort on the writable stream unconditionally and discards the returned promise, but per the WHATWG Streams standard aborting a locked writable returns a promise that rejects with a TypeError. Because the application holds a writer on that writable, which is the only way to write, the rejection is never observed and Node's default unhandled-rejection behavior terminates the process. An untrusted server can therefore crash a client with a single abrupt disconnect, with no authentication and no application mistake. This affects undici versions from 7.0.0 up to 7.29.1 and from 8.0.0 up to 8.10.2. Users should upgrade to undici 7.29.1 or 8.10.2. It has a CVSS v3.1 base score of 5.9 (MEDIUM).

How severe is CVE-2026-85014? +

CVE-2026-85014 has a CVSS v3.1 score of 5.9 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0037, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-85014? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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