Urgent: Broken Access Control in miniOrange “OAuth Single Sign On – SSO (OAuth Client)” Plugin (<= 6.26.14) — What WordPress Site Owners Must Do Now

Summary of the issue

Security researcher Jonas Benjamin Friedli disclosed a missing authorization (broken access control) vulnerability in the miniOrange “OAuth Single Sign On – SSO (OAuth Client)” WordPress plugin. Affected versions are up to and including 6.26.14; the vendor released version 6.26.15 to address the issue. The vulnerability is tracked as CVE-2025-10753.

Patch notes indicate the root cause is a missing authorization check in one or more plugin actions. In practical terms, an unauthenticated user could invoke functionality that should be restricted to authenticated or privileged users.

The reported CVSS base score is 5.3. That score places the issue near the medium severity band because the impact is primarily limited to plugin configuration and operations rather than an immediate full site takeover. The real-world risk depends on how the plugin is configured and used on your site.

What does “broken access control / missing authorization” mean?

Broken access control describes situations where the application fails to enforce who can perform specific actions. In WordPress plugins that expose custom endpoints or admin AJAX actions, common developer mistakes include:

• No check with current_user_can() before performing privileged actions.
• No nonce verification for state‑changing operations.
• Allowing actions to execute without any authentication (unauthenticated).
• Relying on obscurity such as unguessable URLs instead of proper authorization logic.

When these checks are missing, unauthenticated actors can trigger functionality intended only for administrators. Consequences vary from benign information disclosure to configuration tampering, unauthorized account linking, or manipulation of OAuth state.

Software afectado y gravedad

• Plugin: OAuth Single Sign On – SSO (OAuth Client)
• Plugin slug: miniorange-login-with-eve-online-google-facebook
• Affected versions: ≤ 6.26.14
• Fixed in: 6.26.15
• CVE: CVE-2025-10753
• Reportado por: Jonas Benjamin Friedli
• Reported issue: Missing authorization / Broken Access Control (OWASP – Broken Access Control)
• Reported CVSS: 5.3 (context matters; WordPress-specific usage may alter risk)

How attackers could (theoretically) abuse this

No exploit code is provided here. To understand plausible risks from a missing authorization check, consider these misuse scenarios:

• Triggering plugin actions that change OAuth settings (toggling connectors, changing callback URLs), disrupting authentication or redirecting users.
• Forcing state transitions during login flows that permit linking an attacker-controlled OAuth identity to an existing account if account linking lacks proper checks.
• Causing the plugin to save OAuth tokens or session artifacts without validation, potentially altering authentication state.
• Creating or modifying plugin-specific database entries, enabling persistent configuration tampering with downstream effects.

Actual impact varies by site. Simple SSO setups without provisioning or role-mapping are less exposed than configurations that automate user creation or role assignment.

Immediate steps to protect your site (quick checklist — do these now)

1. Verify plugin version. If installed and version ≤ 6.26.14, assume vulnerability.
2. Update to 6.26.15 or later immediately whenever possible through the WordPress admin or WP-CLI.
3. Si no puedes actualizar ahora:
   • Temporarily deactivate the plugin if SSO can be paused.
   • Or apply blocking controls at the web server or WAF level to prevent requests to the plugin’s endpoints.
4. Revisar registros for recent suspicious requests and changes (see indicators below).
5. Rotar credenciales sensibles — WordPress admin passwords and any OAuth client secrets configured in the plugin.
6. Habilite MFA for administrative accounts if not already enforced.
7. Copia de seguridad. database and files before making changes.

Detailed mitigation & remediation (recommended workflow)

Step 1 — Confirm presence and version

Check the installed plugin list in WordPress admin (Plugins → Installed Plugins) or via WP‑CLI:

wp plugin list --status=active --format=table
wp plugin get miniorange-login-with-eve-online-google-facebook --field=version

If the plugin is not present, no further action for this plugin is needed.

Step 2 — Update to the fixed version (preferred)

Update to 6.26.15 or later through the admin interface or WP‑CLI:

wp plugin update miniorange-login-with-eve-online-google-facebook

After updating, verify the plugin shows the patched version and test SSO functionality in a non-production or maintenance window first if possible.

Step 3 — If you cannot update immediately

Option A — Deactivate the plugin temporarily:

wp plugin deactivate miniorange-login-with-eve-online-google-facebook

Option B — Apply request-level protections (WAF / web server rules):

• Block or restrict access to plugin AJAX/admin endpoints unless requests include valid nonces or originate from trusted sources.
• Rate-limit requests to the plugin’s endpoints and throttle suspicious patterns.
• Block POST requests that lack expected headers, referrers or nonces used by the site.

Step 4 — Audit configuration and secrets

• Inspect OAuth client IDs/secrets in the plugin; rotate secrets if necessary.
• Confirm redirect/callback URLs are correct and do not point to attacker-controlled domains.
• Temporarily disable features you do not need (e.g., auto-provisioning, automated role mapping) until patched and reviewed.

Step 5 — Monitor and review logs

• Search server access logs and application logs for traffic to plugin endpoints (admin-ajax.php, plugin-specific routes).
• Look for spikes in POST requests, unusual User-Agent values, or requests missing expected nonces/referrers.
• Audit recent user creations, usermeta changes, and any modifications to plugin-related database tables.

Step 6 — Post-remediation verification

• After applying the vendor update, test SSO flows thoroughly.
• Ensure any temporary blocking rules are removed or adjusted so legitimate traffic is not impacted.
• Continue monitoring for anomalous activity for at least 30 days following an update.

Detecting signs of exploitation (indicators of compromise)

Possible signals the vulnerability was exploited:

• Unexpected changes to plugin settings (callback URLs, client IDs, enabled connectors).
• New admin or user accounts that appear created or linked via SSO without authorization.
• Sudden authentication failures or spikes in SSO-related login attempts.
• Server logs showing unauthenticated POST requests to plugin endpoints that result in state changes (HTTP 200/302).
• Database modifications in plugin-specific tables; differences between recent backups can reveal changes.
• Error traces or log entries referencing plugin functions.

If you find evidence of compromise: consider taking the site offline, preserve logs and copies for forensic analysis, and restore from a clean backup where appropriate. Engage experienced incident response personnel for containment and recovery if required.

How to harden your WordPress site against similar plugin vulnerabilities

• Keep core, plugins, and themes updated. Use staging for testing updates before production deployment.
• Eliminar plugins y temas no utilizados para reducir la superficie de ataque.
• Install only well-maintained plugins from reputable authors and review their change history.
• Follow least-privilege: limit admin accounts and enforce role-based access.
• Harden configuration and file permissions for wp-config.php and other sensitive files.
• Require MFA for administrative access and use strong passwords.
• For authentication plugins: verify they validate nonces, check capabilities (current_user_can), sanitize inputs, and restrict redirect/callback URLs.
• Enable file integrity monitoring and alerting for critical changes.
• Mantenga copias de seguridad probadas y un plan de recuperación.

How a WAF / virtual patching can help (neutral guidance)

A Web Application Firewall (WAF) can provide immediate, temporary protection by blocking request patterns that exploit the vulnerable behaviour. Typical WAF mitigations include:

• Blocking unauthenticated requests to plugin admin actions or AJAX endpoints.
• Enforcing presence and validity of WordPress nonces or expected headers for state-changing requests.
• Rate-limiting or throttling suspicious traffic to plugin routes.
• Deploying targeted signatures that match known exploit attempts without disrupting legitimate traffic.

Virtual patching is a stop-gap measure and should never replace applying the vendor fix. Use WAF rules in monitoring mode first, tune to minimise false positives, and remove temporary rules after the plugin is patched and verified.

Appendix: Useful commands, detection tips, and references

WP‑CLI quick checks

wp plugin list --format=table
wp plugin get miniorange-login-with-eve-online-google-facebook --field=version
wp plugin deactivate miniorange-login-with-eve-online-google-facebook

Search server logs (example)

grep -E "miniorange|mo_oauth|admin-ajax.php" /var/log/nginx/access.log | grep -E "POST|GET" | tail -n 200

Look for frequent POSTs from unusual IPs, missing referrers, or requests with odd parameters.

WAF rule strategies (conceptual)

• Block requests to plugin admin endpoints that do not include a valid WordPress nonce.
• Deny POST requests to plugin endpoints from IP ranges that never generate legitimate traffic for your site.
• Rate-limit clients that exceed expected request thresholds to plugin routes.

Test rules carefully to avoid blocking legitimate OAuth callbacks or provider requests.