CVE-2020-5263 is a medium-severity (CVSS 4.9) CWE-522 vulnerability in auth0-js. A fix is available for auth0-js — see the affected versions and patch details below.
Information disclosure through error object in auth0.js
EPSS Exploitation Probability
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.
How urgent is this, really
CVE-2020-5263 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,166 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
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.
auth0-jsnpmDescription
auth0.js (NPM package auth0-js) greater than version 8.0.0 and before version 9.12.3 has a vulnerability. In the case of an (authentication) error, the error object returned by the library contains the original request of the user, which may include the plaintext password the user entered. If the error object is exposed or logged without modification, the application risks password exposure. This is fixed in version 9.12.3
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | auth0-js | ≥ 8.0.0&&< 9.13.2 | 9.13.2npm install auth0-js@9.13.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for auth0-js, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update auth0-js to 9.13.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-5263 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-2020-5263 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2020-5263. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2020-5263 in your dependencies?
O3 Security finds CVE-2020-5263 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.