CVE-2026-84994

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.

• https://github.com/QwikDev/qwik/commit/c1e7444402f9592b5cf9096e10bf303ab4640511
• 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/security/advisories/GHSA-x586-xvc8-g7q6