How severe is CVE-2026-25148?

No CVSS score has been assigned to CVE-2026-25148 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-25148?

CVE-2026-25148 affects the following packages: @builder.io/qwik-city (npm). Ecosystems affected: npm.

How do I fix CVE-2026-25148?

Update @builder.io/qwik-city to 1.19.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-25148 is resolved across your whole dependency graph.

How do I detect CVE-2026-25148 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-2026-25148 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-2026-25148?

O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-25148 can be triaged on real exposure rather than presence alone.

Is CVE-2026-25148 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-25148 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-2026-25148?

CVE-2026-25148 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 25th 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-2026-25148?

CVE-2026-25148 is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2026-25148 published, and has it been updated?

CVE-2026-25148 was published on February 3, 2026 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-2026-25148 — qwik-city

Fix: QwikDev/qwik@fe2d923

CVE-2026-25148 is a Cross-site Scripting (XSS) vulnerability in @builder.io/qwik-city. A fix is available for @builder.io/qwik-city — see the affected versions and patch details below.

Qwik SSR XSS via Unsafe Virtual Node Serialization

Also known asGHSA-m6jq-g7gq-5w3c

Published

Feb 3, 2026

Updated

Aug 12, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Sep 21, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-25148.

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs25th percentile — riskier than 25% 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

35Kdownloads / week

Description

Summary

Description A Cross-site Scripting (CWE-79) vulnerability in Qwik.js' server-side rendering virtual attribute serialization allows a remote attacker to inject arbitrary web scripts into server-rendered pages via virtual attributes. Successful exploitation permits script execution in a victim's browser in the context of the affected origin. This affects qwik-city before version 1.19.0. This has been patched in qwik-city version 1.19.0.

Impact

This vulnerability impacts applications that dynamically populate Virtual Node attributes with keys/values that users can influence. Applications that hard-code these keys/values are unaffected.

Qwik doesn't use traditional hydration. Instead, it serializes application state into the HTML so the client can resume execution from the server-rendered output. To support this, Qwik v1 marks component boundaries with HTML comments. SSR builds comment content for Virtual components by concatenating structural attribute names and values without any escaping or quoting. An attacker-controlled key or value can prematurely close the HTML comment and inject arbitrary HTML/JS.

Successful exploitation permits script execution in a victim’s browser in the context of the affected origin. Additionally, because Qwik uses these serialized comment markers for resumability, breaking comment structure can lead to resume/hydration desync and unexpected client-side behavior.

Patches

This has been patched in qwik-city version 1.19.0. Users are strongly encouraged to update to the latest available release.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`@builder.io/qwik-city`	all versions	1.19.0`npm install @builder.io/qwik-city@1.19.0`

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 1.19.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-25148 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-2026-25148 can be triaged on real exposure rather than presence alone.

Tailored to CVE-2026-25148. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### Summary **Description** A Cross-site Scripting (CWE-79) vulnerability in Qwik.js' server-side rendering virtual attribute serialization allows a remote attacker to inject arbitrary web scripts into server-rendered pages via virtual attributes. Successful exploitation permits script execution in a victim's browser in the context of the affected origin. This affects qwik-city before version 1.19.0. This has been patched in qwik-city version 1.19.0. ### Impact This vulnerability impacts applications that dynamically populate Virtual Node attributes with keys/values that users can influence.

O3 Security · Impact-Aware SCA

Is CVE-2026-25148 in your dependencies?

O3 Security finds CVE-2026-25148 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