Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HSummary
CVE-2026-40879 is a high-severity Uncontrolled Recursion (CWE-674) vulnerability in Nestjs Nest. Its CVSS base score is 7.5 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Endpoint Denial of Service (T1499); ranked at the 26th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SI-10 (Information Input Validation) and SC-5 (Denial-of-service Protection) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-40879 is a stack overflow vulnerability in the Nest framework, used for building scalable Node.js server-side applications. In versions prior to 11.1.19, the handleData() function recurses once per small, valid JSON message when an attacker sends many such messages in a single TCP frame. Although the buffer shrinks with each recursive call, the maxBufferSize limit is never reached, causing a call stack overflow and triggering a RangeError. A payload of approximately 47 KB is sufficient to exploit this issue, which is classified as CWE-674 (Uncontrolled Recursion).
A remote, unauthenticated attacker can exploit this vulnerability over the network (AV:N) with low attack complexity (AC:L), no privileges (PR:N), and no user interaction (UI:N). Successful exploitation leads to a denial of service through server crash, with a CVSS v3.1 base score of 7.5 (high availability impact, no confidentiality or integrity impact, unchanged scope).
The issue was addressed in Nest version 11.1.19. Security practitioners should upgrade to this version or later to mitigate the vulnerability. Additional details are available in the GitHub Security Advisory at https://github.com/nestjs/nest/security/advisories/GHSA-hpwf-8g29-85qm.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-24264
Vulnerability Data
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;…
more
call stack overflows instead. A ~47 KB payload is sufficient to trigger RangeError. This vulnerability is fixed in 11.1.19.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Input validation can reject or constrain data that would otherwise drive unbounded recursive calls.
DoS protection mechanisms limit the resource-exhaustion impact of uncontrolled recursion without eliminating the flaw.
System monitoring can observe anomalous resource consumption that signals runaway recursion after it begins.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices directly prevent coding errors such as missing recursion limits or termination conditions.
Runtime monitoring of compute resources can detect excessive consumption caused by uncontrolled recursion.
Vulnerability identification processes can discover and record uncontrolled recursion flaws before deployment.
Capacity monitoring and resource provisioning can absorb or limit the impact of runaway recursion.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing in development can detect excessive recursion via static analysis or fuzzing.
Secure development life cycle requires controls that prevent uncontrolled recursion through design and code review.
Application security requirements can mandate recursion limits or stack-depth checks.
Secure system architecture principles include resource-management and input-validation rules that limit recursion.
Secure coding standards directly prohibit or constrain recursive constructs that could exhaust stack or memory.
Capacity management includes monitoring and limits that mitigate resource exhaustion from runaway recursion.