CVE-2026-40879

Name: CVE-2026-40879
Creator: NVD / NIST
Published: 2026-04-21T20:17:01.533+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 0.33%

Last modified Jun 17, 2026

CVE-2026-40879 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. Nest is a framework for building scalable Node.js server-side applications. Prior to 11.1.19, when an attacker sends many small, valid JSON messages in one TCP frame, handleData() recurses once per message; the buffer shrinks each call. EPSS estimates a 0.33% chance of exploitation in the next 30 days.

Description

Nest is a framework for building scalable Node.js server-side applications. Prior to 11.1.19, when an attacker sends many small, valid JSON messages in one TCP frame, handleData() recurses once per message; the buffer shrinks each call. maxBufferSize is never reached; call stack overflows instead. A ~47 KB payload is sufficient to trigger RangeError. This vulnerability is fixed in 11.1.19.

Metrics

CVSS 3.1

7.5/10

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

EPSS Probability

0.33%

24.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-674

Affected Software

Vendor	Product	Versions
Nestjs	Nest	< 11.1.19

References

https://github.com/nestjs/nest/security/advisories/GHSA-hpwf-8g29-85qmVendor Advisory

Timeline

Published: Apr 21, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-40879?

How severe is CVE-2026-40879?

CVE-2026-40879 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 0.33% probability of exploitation in the next 30 days.

How do I fix CVE-2026-40879?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-40879?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST