CVE-2023-39345 — @strapi/plugin-users-perm…
HIGHCVE-2023-39345 is a high-severity (CVSS 7.6) Improper Authentication vulnerability in @strapi/plugin-users-permissions. 1 public exploit reference exists, so weaponization risk is real. A fix is available for @strapi/plugin-users-permissions — see the affected versions and patch details below.
Unauthorized Access to Private Fields in User Registration API in strapi
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for CVE-2023-39345.
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-2023-39345 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 378,156 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.
@strapi/plugin-users-permissionsnpm@strapi/strapinpmDescription
System Details
| Name | Value |
|---|---|
| OS | Windows 11 |
| Version | 4.11.1 (node v16.14.2) |
| Database | mysql |
Description
I marked some fields as private fields in user content-type, and tried to register as a new user via api, at the same time I added content to fill the private fields and sent a post request, and as you can see from the images below, I can write to the private fields.




To prevent this, I went to the extension area and tried to extend the register method, for this I wanted to do it using the sanitizeInput function that I know in the source codes of the strap. But the sanitizeInput function did not filter out private fields.
const { auth } = ctx.state;
const data = ctx.request.body;
const userSchema = strapi.getModel("plugin::users-permissions.user");
sanitize.contentAPI.input(data, userSchema, { auth });
here's the solution I've temporarily kept to myself, code snippet
const body = ctx.request.body;
const { attributes } = strapi.getModel("plugin::users-permissions.user");
const sanitizedData = _.omitBy(body, (data, key) => {
const attribute = attributes[key];
if (_.isNil(attribute)) {
return false;
}
//? If you want, you can throw an error for fields that we did not expect.
// if (_.isNil(attribute))
// throw new ApplicationError(`Unexpected value ${key}`);
// if private value is true, we do not want to send it to the database.
return attribute.private;
});
return sanitizedData;
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @strapi/plugin-users-permissions | ≥ 4.0.0&&< 4.13.1 | 4.13.1npm install @strapi/plugin-users-permissions@4.13.1 |
| 📦npm | @strapi/strapi | ≥ 4.0.0&&< 4.13.1 | 4.13.1npm install @strapi/strapi@4.13.1 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @strapi/plugin-users-permissions, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @strapi/plugin-users-permissions to 4.13.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-39345 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-2023-39345 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2023-39345. 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-2023-39345 in your dependencies?
O3 Security finds CVE-2023-39345 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.