High 8.7Published Oct 13, 2026

CVE-2026-84994Qwik: Crashing any Qwik Server via Resource thenable

Updated under an hour ago (2026-10-19 08:40 UTC)

Does this affect you?

It affects QwikDev qwik and 1 other product. Add what you run to find out whether that includes you.

EPSS puts the chance of exploitation in the next 30 days at 0.52%, higher than 43% of scored CVEs.

Do this next

Start free and add your stack

Free account, 1 product

Every CVE for QwikDev qwik

Exploited in the last 30 days

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.

CVSS: 8.7 HIGH (v4.0, CNA)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
Weakness (CWE): CWE-248
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): 0.52% (percentile 43)
Assigned by: GitHub_M
NVD analysis: Awaiting Analysis
Record last updated: Oct 14, 2026
First seen by InfoSec Signals: Oct 13, 2026

Affected products

Affected products

QwikDev qwik qwikdev:qwik (from the name)	before 2.0.0-beta37	CNA record
@builder.io qwik builder.io:qwik (from the name)	before 1.20.0	CNA record

References

https://github.com/QwikDev/qwik/security/advisories/GHSA-x586-xvc8-g7q6x-refsource-confirm
https://github.com/QwikDev/qwik/pull/8655x-refsource-misc
https://github.com/QwikDev/qwik/commit/c1e7444402f9592b5cf9096e10bf303ab4640511x-refsource-misc
https://github.com/QwikDev/qwik/releases/tag/@builder.io/qwik@1.20.0x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.