Qwik City has a CSRF Protection Bypass via Content-Type Header Validation

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

5.9 · CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:H/A:N

EPSS

• CVE-2026-25151: 0.18% estimated exploitation activity in the next 30 days; percentile 7.74 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary Qwik City’s server-side request handler inconsistently interprets HTTP request headers, which can be abused by a remote attacker to circumvent form submission CSRF protections using specially crafted or multi-valued Content-Type headers. Impact A vulnerability in checkCSRF lets an attacker bypass Origin-based CSRF checks by using malformed or multi-valued Content-Type headers. Exploitation requires the CORS preflight to succeed (so it’s blocked if preflight is denied) and is possible when the application accepts cross-origin requests or via non-browser clients. Impact varies with server CORS and cookie policies and may enable unauthorized state changes.

Published by the source

3 Feb 2026, 20:49 UTC

Last modified by the source

4 Feb 2026, 18:08 UTC

Source last checked

26 Oct 2026, 12:42 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-r666-8gjf-4v5f

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-r666-8gjf-4v5f

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# Patch Next advisory brief: CVE-2026-25151

Advisory: Qwik City has a CSRF Protection Bypass via Content-Type Header Validation
IDs: CVE-2026-25151, GHSA-r666-8gjf-4v5f
Record: https://patchnext.com/advisories/cve-2026-25151 (revision 2, source checked 26 Oct 2026, 12:42 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.9)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: @builder.io/qwik-city 1.19.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm @builder.io/qwik-city: affected < 1.19.0; fixed in 1.19.0

## Suggested inspection (read-only)
- `npm ls @builder.io/qwik-city --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on @builder.io/qwik-city.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-r666-8gjf-4v5f (OSV record GHSA-r666-8gjf-4v5f lists affected ranges: npm @builder.io/qwik-city >=0 <1.19.0 (fixed))
- Verified: https://github.com/advisories/GHSA-r666-8gjf-4v5f (GitHub-reviewed advisory GHSA-r666-8gjf-4v5f lists affected ranges: npm @builder.io/qwik-city >=0 <1.19.0)

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