# CVE-2026-40879

> Vulnerability · severity: **HIGH** (CVSS 7.5).

## 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.

## Key facts

- **CVE ID:** CVE-2026-40879
- **Published:** 2026-04-21
- **CVSS severity:** HIGH
- **CVSS base score:** 7.5
- **CWE codes:** CWE-674

## Affected products

- `nestjs:nest`

## Primary sources

- NIST NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-40879

## Citation

> AI Analytics. CVE-2026-40879. Retrieved 2026-07-23 from https://api.ai-analytics.org/cve/CVE-2026-40879. Derived from NIST NVD. Licensed CC0.

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