CVE-2026-40879

Nest: DoS via Recursive handleData in JsonSocket (TCP Transport)

HIGH
7.5
CVSS Score
Published: April 21, 2026 at 07:14 PM UTC
Updated: October 26, 2026 at 09:10 PM UTC
1 product affected across 1 vendorNest

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Severity
HIGH7.5
Exploit prediction
EPSS 0.3%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 11.1.19
Affected range stops below 11.1.19, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (1)

x_refsource_CONFIRMVendor Advisory
Source: cverecord
https://github.com/nestjs/nest/security/advisories/GHSA-hpwf-8g29-85qm

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-674

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