WPO365 Plugin up to 44.1 on WordPress Deprecated Parser process_openidconnect_token id_token authentication replay

Summaryinfo

A vulnerability labeled as critical has been found in WPO365 Plugin up to 44.1. This affects the function Id_Token_Service_Deprecated::process_openidconnect_token of the component Deprecated Parser. The manipulation of the argument id_token results in authentication replay. This vulnerability is known as CVE-2026-104759. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability classified as critical has been found in WPO365 Plugin up to 44.1. Affected is the function Id_Token_Service_Deprecated::process_openidconnect_token of the component Deprecated Parser. The manipulation of the argument id_token with an unknown input leads to a authentication replay vulnerability. CWE is classifying the issue as CWE-294. A capture-replay flaw exists when the design of the product makes it possible for a malicious user to sniff network traffic and bypass authentication by replaying it to the server in question to the same effect as the original message (or with minor changes). This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is shared for download at wordfence.com. This vulnerability is traded as CVE-2026-104759 since 10/02/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 10/10/2026). The MITRE ATT&CK project declares the attack technique as T1040.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-96286). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Type

• WordPress Plugin

Name

• WPO365 Plugin

Version

• 44.0
• 44.1

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CPE 2.2info

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VulDB is the best source for vulnerability data and more expert information about this specific topic.

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