High · CVSS 8.7CVE-2026-84994

Qwik: Crashing any Qwik Server via Resource thenableCVE-2026-84994

Answer in brief

CVE-2026-84994 records a High severity (CVSS 8.7) vulnerability in Qwik: Crashing any Qwik Server via Resource thenable. The current sources do not mark it as known exploited. The current feed maps QwikDev/qwik (generic), @builder.io/qwik (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Oct 13, 2026Updated Oct 13, 2026Source checked Oct 13, 2026First seen by HOL Oct 13, 2026Material review Oct 13, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 8.7
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 8.7. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps QwikDev/qwik (generic), @builder.io/qwik (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
QwikDev/qwikgeneric	<2.0.0-beta37	2.0.0-beta37
@builder.io/qwikgeneric	<1.20.0	1.20.0

Recommended response

Check inventory. Check lockfiles and deployed manifests for QwikDev/qwik, @builder.io/qwik.
Review the reported fix. Update QwikDev/qwik to 2.0.0-beta37; @builder.io/qwik to 1.20.0 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Oct 13, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Oct 13, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Oct 13, 2026

Sources and claim methodology

Upstream source description

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.

Quoted source text, attributed separately from HOL analysis.