---
id: "CVE-2026-123569"
page: "https://infrastack.ai/live/CVE-2026-123569"
kind: "vulnerability"
aliases: ["CVE-2026-123569"]
title: "devalue npm package: sparse arrays drain CPU and memory during serialization"
severity: "high"
cvss: 8.7
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["devalue", "node", "npm", "package", "server-side-serialization"]
not_affected_if: ["no-devalue-dependency", "no-server-serialization"]
published_at: "2026-11-08T02:16:49+00:00"
first_seen_at: "2026-11-08T02:21:12+00:00"
updated_at: "2026-11-08T02:22:59+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-123569", "first_seen_at": "2026-11-08T02:21:12+00:00"}]
exploit_sources: []
---

# devalue npm package: sparse arrays drain CPU and memory during serialization

Link for people: https://infrastack.ai/live/CVE-2026-123569 (this .md is for agents)

The devalue npm package before 5.6.3 uses excessive CPU and memory when serializing sparse arrays with uneval or stringify. An attacker who gets a sparse array created on the server and serialized there can cause a denial of service.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed devalue version with `npm ls devalue` in each project.
- Look for devalue in package.json dependencies and lockfiles.

## Fix

- devalue: upgrade to `5.6.3` or later.

## Timeline

- 2026-11-08T02:21:12+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-123569

## Documents

- [advisory] Vendor advisory: github.com https://github.com/sveltejs/devalue/security/advisories/GHSA-33hq-fvwr-56pm
- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/devalue-before-5.6.3-denial-of-service-via-sparse-array-serialization

## From the sources

The devalue package for npm before 5.6.3 can consume excessive CPU and memory when serializing sparse arrays with uneval or stringify. An attacker who manages to get a sparse array created on the server, which mainstream wire formats do not allow, and serialized there can cause a denial of service.

---

_Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai_