---
id: CVE-2026-84994
title: Qwik is a performance-focused JavaScript framework
summary: >-
  Qwik is a performance-focused JavaScript framework. Prior to @builder.io/qwik
  1.20.0 and @qwik.dev/core 2.0.0-beta.37, default server-side qwik-json
  deserialization causes ResourceSerializer.$fill$ to pass resource._resolved to
  Promise.r…
severity: high
cwe:
  - CWE-248
published: '2026-10-13'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T17:19:46.043'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-84994'
references:
  - url: >-
      https://github.com/QwikDev/qwik/commit/c1e7444402f9592b5cf9096e10bf303ab4640511
    label: security-advisories@github.com
  - url: 'https://github.com/QwikDev/qwik/pull/8655'
    label: security-advisories@github.com
  - url: 'https://github.com/QwikDev/qwik/releases/tag/@builder.io/qwik@1.20.0'
    label: security-advisories@github.com
  - url: 'https://github.com/QwikDev/qwik/security/advisories/GHSA-x586-xvc8-g7q6'
    label: security-advisories@github.com
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-84994'
  - url: 'https://github.com/advisories/GHSA-x586-xvc8-g7q6'
tags:
  - nvd
  - cve.org
  - ghsa
  - npm
epss: 0.00524
epssPercentile: 0.44275
ingestedAt: '2026-10-13T19:43:29.150Z'
vendor: QwikDev
product: qwik
affected:
  - qwik < 2.0.0-beta37
  - qwik < 1.20.0
cvss: 8.7
cvssVector: 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-10-14T16:35:04.214453Z'
cvssSource: cna
aliases:
  - GHSA-x586-xvc8-g7q6
ecosystem: npm
patched:
  - '@builder.io/qwik 1.20.0'
  - '@qwik.dev/core 2.0.0-beta37'
---

## Overview

Qwik is a performance-focused JavaScript framework. Prior to @builder.io/qwik 1.20.0 and @qwik.dev/core 2.0.0-beta.37, default server-side qwik-json deserialization causes ResourceSerializer.$fill$ to pass resource._resolved to Promise.resolve without first rejecting attacker-controlled thenables. An unauthenticated request can provide a plain object whose then property is a QRL for an unregistered symbol, causing an orphaned asynchronous rejection that terminates Node.js under its default unhandled-rejection policy. A single request can crash a server, and repeated requests can keep replicas unavailable. This issue is fixed in @builder.io/qwik 1.20.0 and @qwik.dev/core 2.0.0-beta.37.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-84994)

Affected packages:

- `@builder.io/qwik < 1.20.0`
- `@qwik.dev/core < 2.0.0-beta37`

Patched in:

- `@builder.io/qwik 1.20.0`
- `@qwik.dev/core 2.0.0-beta37`

Source: https://github.com/advisories/GHSA-x586-xvc8-g7q6