nestjs nest up to 11.1.18 JSON Message handleData recursion

Summaryinfo

A vulnerability identified as problematic has been detected in nestjs nest up to 11.1.18. This affects the function handleData of the component JSON Message Handler. This manipulation causes recursion. This vulnerability is handled as CVE-2026-40879. The attack can be initiated remotely. There is not any exploit available. You should upgrade the affected component.

Detailsinfo

A vulnerability has been found in nestjs nest up to 11.1.18 and classified as problematic. Affected by this vulnerability is the function handleData of the component JSON Message Handler. The manipulation with an unknown input leads to a recursion vulnerability. The CWE definition for the vulnerability is CWE-674. The product does not properly control the amount of recursion that takes place, consuming excessive resources, such as allocated memory or the program stack. As an impact it is known to affect availability. The summary by CVE is:

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.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2026-40879 since 04/15/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1499 according to MITRE ATT&CK.

Upgrading to version 11.1.19 eliminates this vulnerability.

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Productinfo

Vendor

• nestjs

Name

• nest

Version

• 11.1.0
• 11.1.1
• 11.1.2
• 11.1.3
• 11.1.4
• 11.1.5
• 11.1.6
• 11.1.7
• 11.1.8
• 11.1.9
• 11.1.10
• 11.1.11
• 11.1.12
• 11.1.13
• 11.1.14
• 11.1.15
• 11.1.16
• 11.1.17
• 11.1.18

Website

• Product: https://github.com/nestjs/nest/

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