How severe is GHSA-r666-8gjf-4v5f?

GHSA-r666-8gjf-4v5f has a CVSS score of 5.9/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by GHSA-r666-8gjf-4v5f?

GHSA-r666-8gjf-4v5f affects the following packages: @builder.io/qwik-city (npm). Ecosystems affected: npm.

How do I fix GHSA-r666-8gjf-4v5f?

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 GHSA-r666-8gjf-4v5f is resolved across your whole dependency graph.

How do I detect GHSA-r666-8gjf-4v5f in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @builder.io/qwik-city. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate GHSA-r666-8gjf-4v5f 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 GHSA-r666-8gjf-4v5f?

O3 pinpoints whether GHSA-r666-8gjf-4v5f is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-r666-8gjf-4v5f actively exploited in the wild?

No public exploit code has been indexed for GHSA-r666-8gjf-4v5f 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 GHSA-r666-8gjf-4v5f?

GHSA-r666-8gjf-4v5f has an EPSS (Exploit Prediction Scoring System) score of 0.2%, placing it in the 5th 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 GHSA-r666-8gjf-4v5f?

GHSA-r666-8gjf-4v5f is classified as Cross-Site Request Forgery (CSRF) (CWE-352). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-r666-8gjf-4v5f published, and has it been updated?

GHSA-r666-8gjf-4v5f was published on February 3, 2026 and was last updated on February 4, 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

GHSA-r666-8gjf-4v5f

MEDIUM

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

Also known asCVE-2026-25151

Published

Feb 3, 2026

Updated

Feb 4, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

EPSS Exploitation Probability

via FIRST.org ↗

0.2%probability of exploitation in next 30 days

Lower Risk5th percentile+0.15%

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.

Blast Radius

1 pkg affected

📦@builder.io/qwik-city

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects npm packages — download data is not available via public APIs for these ecosystems.

Description

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.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`@builder.io/qwik-city`	all versions	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. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
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 GHSA-r666-8gjf-4v5f 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 pinpoints whether GHSA-r666-8gjf-4v5f is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-r666-8gjf-4v5f. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### 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 w

O3 Security · Impact-Aware SCA

Is GHSA-r666-8gjf-4v5f in your dependencies?

O3 detects GHSA-r666-8gjf-4v5f across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works