Is CVE-2026-40879 actively exploited?

No active exploitation of CVE-2026-40879 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2026-40879 be exploited remotely?

Yes. CVE-2026-40879 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2026-40879?

CVE-2026-40879 has a CVSS score of 7.5 (HIGH).

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HIGH

CVE-2026-40879

CWE-674Published: April 21, 2026· Updated: Apr 24, 2026

7.5

CVSS v3.1

EPSS:0.04%probability of exploitation in 30 daysPercentile:12.2th

Official 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.

NVD Source

Technical Analysis

CVE-2026-40879 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in availability disruption (denial of service), with a CVSS base score of 7.5.