Summary
Qwik: Crashing any Qwik Server via Resource thenable
A Qwik server in the default configuration can be crashed with one unauthenticated HTTP request. During qwik-json body parsing, ResourceSerializer.$fill$ does Promise.resolve(resource._resolved). If _resolved is a plain object whose .then is a QRL for an unregistered symbol, the async QRL rejects, the rejection is orphaned, and Node terminates the process via its default unhandled-rejection policy.
Impact
One unauthenticated request crashes the server. Looping keeps every replica dead as long as the attacker sends requests.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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@builder.io/qwik to 1.20.0 or later; @qwik.dev/core to 2.0.0-beta37 or later
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2026-84994? CVE-2026-84994 is a high-severity security vulnerability in @builder.io/qwik (npm), affecting versions < 1.20.0. It is fixed in 1.20.0, 2.0.0-beta37.
- Which packages are affected by CVE-2026-84994?
@builder.io/qwik(npm) (versions < 1.20.0)@qwik.dev/core(npm) (versions < 2.0.0-beta37)
- Is there a fix for CVE-2026-84994? Yes. CVE-2026-84994 is fixed in 1.20.0, 2.0.0-beta37. Upgrade to this version or later.
- Is CVE-2026-84994 exploitable, and should I be worried? Whether CVE-2026-84994 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-84994 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-84994?
- Upgrade
@builder.io/qwikto 1.20.0 or later - Upgrade
@qwik.dev/coreto 2.0.0-beta37 or later
- Upgrade