CVE-2026-16261 Overview
CVE-2026-16261 affects the login-social WordPress plugin through version 1.0.4. The plugin fails to validate password-reset requests against a reset key or the requester's identity. It also issues authentication sessions from unverified third-party sign-in data. Unauthenticated attackers can reset any user's password or log in as any existing account, including administrators. Successful exploitation leads to full site takeover. The vulnerability is classified under CWE-287 (Improper Authentication).
Critical Impact
Remote, unauthenticated attackers can hijack administrator accounts and take over affected WordPress sites without any user interaction.
Affected Products
- login-social WordPress plugin, all versions through 1.0.4
- WordPress sites with the login-social plugin activated
- Administrator accounts on affected installations
Discovery Timeline
- 2026-08-02 - CVE-2026-16261 published to NVD
- 2026-08-03 - Last updated in NVD database
Technical Details for CVE-2026-16261
Vulnerability Analysis
The login-social plugin exposes two distinct authentication weaknesses within the same code path family. The first defect involves the password-reset workflow. The plugin accepts reset requests without verifying a reset key or confirming that the request originates from the account owner. Any attacker can submit a reset request targeting an arbitrary username and receive a new credential set.
The second defect involves social sign-in handling. The plugin issues WordPress authentication sessions based on third-party identity data that it does not verify. An attacker can forge or replay sign-in data referencing any existing WordPress account. The plugin then establishes a session under that identity, including administrator accounts.
Both flaws align with CWE-287, Improper Authentication. Compromise results in full administrative control, arbitrary content modification, plugin and theme installation, and persistent backdoor deployment.
Root Cause
The plugin trusts client-supplied identity information at two authentication decision points. Password-reset endpoints do not enforce the standard WordPress reset-key mechanism. Social sign-in handlers do not cryptographically verify assertions returned from third-party identity providers. This produces a bypass of both the reset workflow and the primary authentication path.
Attack Vector
Exploitation requires only network access to the target site. No authentication or user interaction is needed. An attacker submits crafted requests to the plugin's password-reset or social sign-in endpoints referencing a target account, then authenticates as that user. Refer to the WPScan Vulnerability Report for endpoint specifics.
Detection Methods for CVE-2026-16261
Indicators of Compromise
- Unexpected wp_users password hash changes without corresponding password-reset emails delivered to the user
- Successful administrator logins from unfamiliar IP addresses or geolocations following requests to login-social plugin endpoints
- New administrator accounts, plugin installations, or theme uploads shortly after social sign-in requests
- Web server access logs showing repeated POST requests to login-social plugin routes referencing multiple usernames
Detection Strategies
- Monitor WordPress audit logs for password changes not preceded by a validated reset-key email flow
- Correlate authentication events with requests to plugin endpoints associated with login-social
- Alert on privilege changes, new administrator role assignments, and plugin/theme installation events
Monitoring Recommendations
- Enable verbose logging on the WordPress site and forward events to a centralized SIEM for correlation
- Track file integrity for wp-content/plugins/, wp-content/themes/, and root WordPress files
- Review external references such as the WPScan Vulnerability Report for updated indicators
How to Mitigate CVE-2026-16261
Immediate Actions Required
- Deactivate and remove the login-social plugin from all WordPress installations until a fixed version is confirmed available
- Force a password reset for all users, prioritizing administrator and editor accounts
- Invalidate all active WordPress sessions using wp_destroy_all_sessions or the equivalent administrative action
- Audit user accounts for unauthorized additions or role changes and revert them
Patch Information
At the time of publication, no fixed version beyond 1.0.4 is referenced in the available advisory data. Monitor the WPScan Vulnerability Report and the WordPress plugin directory for a patched release. Apply updates immediately when published.
Workarounds
- Remove the login-social plugin entirely and rely on native WordPress authentication until a patch is verified
- Restrict access to wp-login.php and plugin endpoints using web application firewall rules or IP allowlisting
- Enforce two-factor authentication on all privileged accounts to reduce the impact of session issuance flaws
# Disable the vulnerable plugin via WP-CLI
wp plugin deactivate login-social
wp plugin delete login-social
# Force password reset and session invalidation for all users
wp user list --field=ID | xargs -I {} wp user reset-password {} --skip-email
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
