Simple JWT Login <= 3.6.6 - Authenticated (Subscriber+) Authentication Bypass to Privilege Escalation via 'payload' Parameter
The Simple JWT Login – Allows you to use JWT on REST endpoints. plugin for WordPress is vulnerable to Authentication Bypass to Privilege Escalation in all versions up to, and including, 3.6.6 via the `payload` parameter. The vulnerability exists because `AuthenticateService::generatePayload()` only overwrites JWT payload keys whose names appear in the admin-configured `jwt_payload` list — leaving any attacker-supplied identity claims such as `email`, `id`, or `username` intact and signed into the JWT with the site's HS256 secret. This makes it possible for authenticated attackers, with subscriber-level access and above, to escalate their privileges to that of an Administrator by injecting a target administrator's email address into the `payload` parameter at the `/wp-json/simple-jwt-login/v1/auth` endpoint, then redeeming the resulting JWT at the `/autologin` endpoint to obtain a fully authenticated session as that administrator.
Quick answer
Simple JWT Login – Allows you to use JWT on REST endpoints. should be reviewed and updated if it matches the affected versions. The recommended fix is to apply the vendor-supported patched version or the mitigation steps below, then retest the public website with Fixnx.
Who is affected
Affected versions
- *-3.6.6
Fixed versions
- 3.6.7
How to fix it
Simple JWT Login – Allows you to use JWT on REST endpoints. is affected by CVE-2026-14262, a authentication bypass issue in versions up to 3.6.6. Wordfence lists the official remediation as updating to version 3.6.7, or a newer patched version. Prioritize internet-facing WordPress sites, sites with public registration, customer portals, and admin workflows where the vulnerable feature is enabled. If immediate patching is not possible, disable the affected plugin or vulnerable feature, restrict access, and monitor for exploitation until the update is installed.
- Inventory every WordPress site that has Simple JWT Login – Allows you to use JWT on REST endpoints. installed, including staging, multisite, client, and WooCommerce environments.
- Confirm the installed Simple JWT Login – Allows you to use JWT on REST endpoints. version and compare it with the affected range from the Wordfence advisory.
- Update Simple JWT Login – Allows you to use JWT on REST endpoints. to version 3.6.7, or to a newer vendor-supported patched version from the official WordPress update channel.
- If the update cannot be applied immediately, disable Simple JWT Login – Allows you to use JWT on REST endpoints. or the affected feature and restrict access with roles, authentication, WAF rules, or temporary route blocking.
- Review affected REST endpoints, AJAX actions, roles, capabilities, orders, appointments, account records, and payment or status changes for unauthorized activity.
- Rotate administrator sessions, API keys, webhook secrets, and integration tokens if logs or content review suggest compromise.
- Clear WordPress, object, CDN, page-builder, and browser caches after patching so vulnerable assets or stored payloads are not served.
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Verify the fix
- Confirm the running Simple JWT Login – Allows you to use JWT on REST endpoints. version is version 3.6.7 or newer, and record the patched version in the remediation ticket.
- Verify unauthenticated or low-privilege users can no longer trigger the affected action, endpoint, payment, appointment, account, or settings change.
- Review web server, WordPress, security plugin, WAF, and application logs for exploitation attempts before and after the fix.
- Retest normal user, admin, checkout, form, API, or integration workflows to confirm the update did not break expected behavior.
- Run a fresh Fixnx scan and document the public exposure state, patched version, log review, and any cleanup evidence.
Related categories
Trusted references
FAQ
What is affected by CVE-2026-14262?
Simple JWT Login – Allows you to use JWT on REST endpoints. versions listed as affected should be reviewed: *-3.6.6.
What should I fix first?
Start with internet-facing sites, admin panels, login flows, plugins, themes, modules, packages, and systems that process user-controlled input or sensitive data.
How do I confirm the fix worked?
Apply the patched version or mitigation, clear caches where relevant, retest the affected workflow, and run a new Fixnx scan to verify public website exposure signals.
How are Fixnx security risk categories chosen?
Fixnx keeps one canonical risk page and assigns only broad, relevant categories such as ecosystem, technology area, or vulnerability class.