---
title: "CVE-2026-84994: Qwik - Denial of Service"
description: "Qwik prior to @builder.io/qwik 1.20.0 and @qwik.dev/core 2.0.0-beta.37 contains a denial of service caused by improper handling of attacker-controlled thenables in server-side qwik-json deserialization, letting unauthenticated attackers crash Node.js servers, exploit requires sending crafted unauthenticated requests."
url: https://panop.io/threat-heartbeat/CVE-2026-84994/
---

# CVE-2026-84994 Qwik - Denial of Service

Qwik prior to @builder.io/qwik 1.20.0 and @qwik.dev/core 2.0.0-beta.37 contains a denial of service caused by improper handling of attacker-controlled thenables in server-side qwik-json deserialization, letting unauthenticated attackers crash Node.js servers, exploit requires sending crafted unauthenticated requests.

CVSS base score 8.7 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

EPSS

0.52% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-84994)

## Details

Type

Denial of Service

Impact

Denial Of Service

CVSS vector

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Published

13 October 2026

Updated

15 October 2026

Weakness

[CWE-248](https://cwe.mitre.org/data/definitions/248.html)

## Vendor fix

Update to @builder.io/qwik 1.20.0 and @qwik.dev/core 2.0.0-beta.37 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-84994](https://nvd.nist.gov/vuln/detail/CVE-2026-84994)
- [https://github.com/QwikDev/qwik/commit/c1e7444402f9592b5cf9096e10bf303ab4640511](https://github.com/QwikDev/qwik/commit/c1e7444402f9592b5cf9096e10bf303ab4640511)
- [https://github.com/QwikDev/qwik/pull/8655](https://github.com/QwikDev/qwik/pull/8655)
- [https://github.com/QwikDev/qwik/releases/tag/@builder.io/qwik@1.20.0](https://github.com/QwikDev/qwik/releases/tag/@builder.io/qwik@1.20.0)
- [https://github.com/QwikDev/qwik/security/advisories/GHSA-x586-xvc8-g7q6](https://github.com/QwikDev/qwik/security/advisories/GHSA-x586-xvc8-g7q6)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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