GHSA-954c-jjx6-cxv7
HIGHGHSA-954c-jjx6-cxv7 is a high-severity (CVSS 8) Cross-site Scripting (XSS) vulnerability in @auth0/nextjs-auth0. O3 Security confirms whether GHSA-954c-jjx6-cxv7 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Reflected XSS from the callback handler's error query parameter
Blast Radius
Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.
@auth0/nextjs-auth0npmDescription
Overview
Versions before and including 1.4.1 are vulnerable to reflected XSS. An attacker can execute arbitrary code by providing an XSS payload in the error query parameter which is then processed by the callback handler as an error message.
Am I affected?
You are affected by this vulnerability if you are using @auth0/nextjs-auth0 version 1.4.1 or lower unless you are using custom error handling that does not return the error message in an HTML response.
How to fix that?
Upgrade to version 1.4.2.
Will this update impact my users?
The fix adds basic HTML escaping to the error message and it should not impact your users.
Credit
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @auth0/nextjs-auth0 | all versions | 1.4.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @auth0/nextjs-auth0. 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 @auth0/nextjs-auth0 to 1.4.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-954c-jjx6-cxv7 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-954c-jjx6-cxv7 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-954c-jjx6-cxv7. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-954c-jjx6-cxv7 in your dependencies?
O3 detects GHSA-954c-jjx6-cxv7 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.