CVE-2026-123875: Null Dereference (CVSS 5.9)

Description

A NULL pointer dereference in Node.js HTTP/2 lets an unauthenticated client crash the server, over both TLS and cleartext, by cancelling file downloads. When the server serves a file with stream.respondWithFile() or stream.respondWithFD() and the client cancels the request, a StreamPipe used for the transfer is torn down in an order that leaves a NULL pointer which is then dereferenced, aborting the process. No crafted frames are needed, and a handful of cancelled requests against a default file-serving handler is enough. This vulnerability affects Node.js 26.x, 24.x, and 22.x.

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CVSS v3.1 Score

5.9

MEDIUM

CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS — Exploit Prediction

0.0040

Probability of exploitation

0.34%

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-476 CWE-476

References

Other References

https://cna.openjsf.org/security-advisories.html https://nodejs.org/en/blog/vulnerability/november-2026-security-releases

Frequently Asked Questions

What is CVE-2026-123875? +

A NULL pointer dereference in Node.js HTTP/2 lets an unauthenticated client crash the server, over both TLS and cleartext, by cancelling file downloads. When the server serves a file with stream.respondWithFile() or stream.respondWithFD() and the client cancels the request, a StreamPipe used for the transfer is torn down in an order that leaves a NULL pointer which is then dereferenced, aborting the process. No crafted frames are needed, and a handful of cancelled requests against a default file-serving handler is enough. This vulnerability affects Node.js 26.x, 24.x, and 22.x. It has a CVSS v3.1 base score of 5.9 (MEDIUM).

How severe is CVE-2026-123875? +

CVE-2026-123875 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 0.0040, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-123875? +

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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