# CVE-2026-104759: WPO365 Login authentication bypass via OIDC nonce replay

Source: https://junglewise.ai/threats/cve-2026-104759-the-wpo365-seamless-wordpress-microsoft-integration-wpo365-login  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-10. Updated: 2026-10-16  
License: CC BY 4.0 with a link back

CVE-2026-104759 · Severity: high · CVSS 8.1 · Published 2026-10-10

WPO365 Login is a WordPress plugin that integrates Microsoft account authentication. The plugin fails to properly validate security tokens in its OpenID Connect implementation, allowing attackers who possess a previously-valid login token to reuse it and log in as any user, including administrators. This enables complete takeover of WordPress sites using affected versions.

Technologies: [WPO365 | Login](https://junglewise.ai/threats/technologies/wpo365-login). Vendors: [WPO365](https://junglewise.ai/threats/vendors/wpo365).

## Quick answers

**Is CVE-2026-104759 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-104759 being exploited in the wild.

**How severe is CVE-2026-104759?** High severity, with a CVSS score of 8.1, published 10 October 2026.

**Which products and versions are affected?** WPO365 | Login up to and including 44.1.

**Is there a fix for CVE-2026-104759?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-104759 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-104759?** Check whether you run WPO365 | Login at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability exists in Id_Token_Service_Deprecated::process_openidconnect_token(), which uses WordPress's wp_verify_nonce() function to validate a 64-character hex nonce created by Nonce_Service::create_nonce(). Since wp_verify_nonce() cannot verify this nonce format, the check silently fails without terminating authentication. An unauthenticated attacker with a previously-issued valid id_token can replay it to authenticate as any user. The flaw only affects installations with the use_id_token_parser_v2 plugin option enabled.

## Affected products

- WPO365 WPO365 Login up to and including 44.1

## Timeline

- 2026-10-10: disclosed

## References

- [https://plugins.trac.wordpress.org/browser/wpo365-login/tags/44.1/Services/Id_Token_Service.php](https://plugins.trac.wordpress.org/browser/wpo365-login/tags/44.1/Services/Id_Token_Service.php)
- [https://plugins.trac.wordpress.org/browser/wpo365-login/tags/44.1/Services/Id_Token_Service_Deprecated.php](https://plugins.trac.wordpress.org/browser/wpo365-login/tags/44.1/Services/Id_Token_Service_Deprecated.php)

## Related threats

- [WPO365 | LOGIN stored cross-site scripting in id_token](https://junglewise.ai/threats/cve-2026-96765-the-wpo365-seamless-wordpress-microsoft-integration-wpo365-login)
- [WPO365 Login CSRF in update_settings handler](https://junglewise.ai/threats/cve-2026-15212-wpo365-login-csrf-in-update-settings-handler)