CVE-2026-25150: Builder.io Qwik City prototype pollution in form processing

CVE-2026-25150 · Severity: low · CVSS 3.1 · Published 2026-02-03

Qwik City, a framework for building web applications, contains a vulnerability in how it processes form submissions. An attacker can send specially crafted form data to inject malicious code into the application's core object structure, bypassing authentication, escalating privileges, or crashing the service without needing credentials or user interaction.

Technologies: Builder.Io Qwik-City, @builder.io/qwik-city (npm). Vendors: Builder.Io, npm.

Quick answers

Is CVE-2026-25150 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-25150 being exploited in the wild.
How severe is CVE-2026-25150?
Low severity, with a CVSS score of 3.1, published 3 February 2026.
Which products and versions are affected?
Builder.Io Qwik-City < 1.19.0; @builder.io/qwik-city (npm) SEMVER:introduced=0,fixed=1.19.0.
Is there a fix for CVE-2026-25150?
Yes. @builder.io/qwik-city (npm): upgrade to 1.19.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-25150 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-25150?
Check whether you run Builder.Io Qwik-City or @builder.io/qwik-city (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • @builder.io/qwik-city (npm): upgrade to 1.19.0 or later
    npm install @builder.io/qwik-city@1.19.0

Technical details

A prototype pollution vulnerability exists in the formToObj() function within @builder.io/qwik-city middleware. The function converts form field names with dot notation (e.g., user.name) into nested objects but fails to sanitize dangerous property names such as __proto__, constructor, and prototype. An unauthenticated, network-based attacker can send a POST request with crafted form field names to pollute Object.prototype on the server, potentially causing privilege escalation, authentication bypass, denial of service, or other application integrity failures. The vulnerability affects all versions prior to 1.19.0, which contains the fix.

Affected products

  • Builder.io Qwik City < 1.19.0

Identifiers

  • CVE-2026-25150
  • GHSA-xqg6-98cw-gxhq

Timeline

  • 2026-02-03: disclosed
  • 2026-02-03: patched: Fixed in version 1.19.0

References

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