CVE-2026-104759: WPO365 authentication bypass vulnerability

high 8.1 published 2026-10-10 · updated 2026-10-13

Affected versions: 44.1 and older
Fixed in: 45.0 *
Latest version: 45.1
Severity: High · CVSS 8.1
Active installs: 10,000+
Type: Authentication bypass

* The source does not name a fixed version; this is the first wordpress.org release after the last affected version.

What an attacker needs

Access: None. No account or login is needed.

CVSS vector (score by Wordfence): CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

What to do now

Update WPO365 to 45.0 or newer (the latest is 45.1): Dashboard → Updates, or Plugins → “update now”.
If you cannot update right away, deactivate it until you can.
Turn on auto-updates for it: Plugins → “Enable auto-updates” on its row.
Not sure which version you run? Check your version against every known WPO365 issue. With WP-CLI: wp plugin get wpo365-login --field=version.
If you ran an affected version and something looks off (new admin users, spam pages, redirects), run the free scan below.

The advisory

The WPO365 | SEAMLESS WORDPRESS + MICROSOFT INTEGRATION (WPO365 | LOGIN) plugin for WordPress is vulnerable to Authentication Bypass via OIDC Nonce Replay in all versions up to, and including, 44.1 This is due to `Id_Token_Service_Deprecated::process_openidconnect_token()` using the incompatible WordPress core `wp_verify_nonce()` function to validate a nonce produced by `Nonce_Service::create_nonce()` — a 64-character hex value that `wp_verify_nonce()` can never successfully verify — causing the nonce check to silently fail without terminating authentication, so execution continues into `authenticate_oidc_user()` with the attacker-supplied `id_token`. This makes it possible for unauthenticated attackers who have obtained a previously-issued, valid `id_token` for a target account to replay that token and authenticate as any WordPress user, including administrators, resulting in full site takeover. This vulnerability is only exploitable when the `use_id_token_parser_v2` plugin option is enabled, as this is the configuration that routes token processing through the deprecated parser containing the broken nonce check.

Description from the CVE record, published by Wordfence (the CVE Numbering Authority), via the NVD entry for CVE-2026-104759.

References

NVD CVE-2026-104759 nvd.nist.gov
Wordfence advisory www.wordfence.com
Code change (fix) plugins.trac.wordpress.org
Plugin source plugins.trac.wordpress.org

Ran an affected version? Check your site for signs of a hack

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Where this data comes from

CVE record, score and references: NIST National Vulnerability Database (NVD), checked 2026-11-04. This product uses data from the NVD API but is not endorsed or certified by the NVD.
Versions and install counts: wordpress.org/plugins/wpo365-login (Plugins API), fetched 2026-11-04.
The summary, “what an attacker needs” and “what to do” sections are our plain-English reading of the record and the plugin's release history; the quoted description is the record's own text. Spot an error? Email Daniel.