High severity · published Apr 21, 2026
CVE-2026-40879
Nest: DoS via Recursive handleData in JsonSocket (TCP Transport)
7.5
CVSS
0.3%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 26% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
NE
nest · nestjs
< 11.1.19 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-40879
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-40879
Vendor Advisory
https://github.com/nestjs/nest/security/advisories/GHSA-hpwf-8g29-85qm
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