CVE-2026-122220
Received Received - Intake

Authentication Bypass via SAML Replay in WPO365 Login Plugin

Publication date: 2026-11-04

Last updated on: 2026-11-04

Assigner: VulnCheck

Description
WPO365 | LOGIN (wpo365-login) plugin before version 45.2 contains an authentication bypass by capture-replay vulnerability caused by a non-functional anti-replay check in Saml2_Service::check_message_id(), which never persists processed SAML message IDs to the wpo365_saml_message_ids transient due to a logic error that returns before saving. Attackers who capture a validly-signed SAMLResponse can replay it to the ACS endpoint repeatedly within its assertion validity window to log in as the victim, including administrators, without detection since the duplicate message ID check never triggers.

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Meta Information

Published
2026-11-04
Last Modified
2026-11-04
Generated
2026-11-04
AI Q&A
2026-11-04
EPSS Evaluated
N/A
NVD
CVE-2026-122220
EUVD
EUVD-2026-117064

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
wpo365 WPO365 | SEAMLESS WORDPRESS + MICROSOFT INTEGRATION (WPO365 | LOGIN) 0

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
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).

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Executive Summary

This vulnerability is an authentication bypass caused by a flawed SAML replay protection mechanism in the WPO365 plugin before version 45.2. The check_message_id() function fails to save processed SAML message IDs due to a logic error, allowing attackers to replay captured valid SAML responses repeatedly within the assertion validity window to gain unauthorized access, including as administrators.

Detection Guidance

Check WordPress plugin versions for WPO365 | LOGIN. If using version before 45.2, the vulnerability exists. Inspect SAML response logs for repeated identical requests to the ACS endpoint within the assertion validity window.

Impact Analysis

Attackers can capture a valid SAML response and replay it multiple times to log in as any user, including administrators, without detection. This could lead to unauthorized access to sensitive data, privilege escalation, and potential compromise of the WordPress site and connected Microsoft services.

Compliance Impact

This vulnerability could lead to unauthorized access to personal or sensitive data, violating GDPR and HIPAA compliance requirements for data protection and access controls. Organizations using the affected plugin may face legal and regulatory penalties due to potential data breaches.

Mitigation Strategies

Update the WPO365 | LOGIN plugin to version 45.2 or later immediately. Review SAML logs for signs of replay attacks. Disable SAML-based authentication temporarily if suspicious activity is detected.

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