Reported vulnerability
WordPress + Microsoft Office 365 / Azure AD | LOGIN <= 15.3 - Stored Cross-Site Scripting
Published 15 Oct 2021
Updated 22 Jan 2024
CVE-2021-43409
Compare your installed software with the affected versions below. Follow the source’s remediation guidance and test an available update after taking a backup. A database entry describes a reported issue; it does not establish whether a particular website has been compromised.
Does this affect my version?
Check your installed version against this advisory. This compares the report’s version ranges and does not scan your website.
Wordfence advisory
medium · CVSS 6.1The WPO365 | LOGIN WordPress plugin (up to and including version 15.3) by wpo365.com is vulnerable to a persistent Cross-Site Scripting (XSS) vulnerability (also known as Stored or Second-Order XSS). Persistent XSS vulnerabilities occur when the application stores and retrieves client supplied data without proper handling of dangerous content. This type of XSS vulnerability is exploited by submitting malicious script content to the application which is then retrieved and executed by other application users. The attacker could exploit this to conduct a range of attacks against users of the affected application such as session hijacking, account take over and accessing sensitive data. In this case, the XSS payload can be submitted by any anonymous user, the payload then renders and executes when a WordPress administrator authenticates and accesses the WordPress Dashboard. The injected payload can carry out actions on behalf of the administrator including adding other administrative users and changing application settings. This flaw could be exploited to ultimately provide full control of the affected system to the attacker.
Severity vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
WPO365 | SEAMLESS WORDPRESS + MICROSOFT INTEGRATION (WPO365 | LOGIN)
- Software
- plugin · wpo365-login
- Affected versions
- Start version unspecified, through 15.3
- Fix availability
- Fix available
- Fixed versions
- 15.4
Recommended action
Update to version 15.4, or a newer patched version
Further references (1)
Data sources and licences
Copyright 2012-2026 Defiant Inc.
Defiant hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute this software vulnerability information. Any copy of the software vulnerability information you make for such purposes is authorized provided that you include a hyperlink to this vulnerability record and reproduce Defiant's copyright designation and this license in any such copy.
Read licence termsCopyright 1999-2026 The MITRE Corporation
CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE®). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy.
Read licence termsSource: Wordfence
Need help fixing this issue?
Get help checking your site, applying an available update and resolving any problems after updating.
Get help with this issueQuestions about this vulnerability
Which versions of WPO365 | SEAMLESS WORDPRESS + MICROSOFT INTEGRATION (WPO365 | LOGIN) are affected?
Wordfence lists these affected versions: Start version unspecified, through 15.3. Use the version checker above to compare your installed release with this report.
Is a fix available for WPO365 | SEAMLESS WORDPRESS + MICROSOFT INTEGRATION (WPO365 | LOGIN)?
Wordfence reports a fix for this issue in WPO365 | SEAMLESS WORDPRESS + MICROSOFT INTEGRATION (WPO365 | LOGIN). It lists these fixed versions: 15.4. Back up your website and test the recommended update before applying it to your live site.
Where can I find my installed plugin version?
In WordPress, open Plugins > Installed Plugins and find the version shown beneath the plugin name.
Does an affected version mean my website has been hacked?
An affected version means the installed release matches a vulnerability described in this report. It does not show whether anyone has exploited it on your website. The checker compares version numbers with stored reports; it does not inspect your website.
Other reports for the same product
These reports cover at least one of the same plugins, themes or WordPress core. Check each report’s affected versions separately.
- WPO365 | SEAMLESS WORDPRESS + MICROSOFT INTEGRATION (WPO365 | LOGIN) <= 44.1 - Unauthenticated Stored Cross-Site Scripting via 'id_token' Parameter (iss / unique_name JWT claims)Updated 10 Oct 2026
- WPO365 | SEAMLESS WORDPRESS + MICROSOFT INTEGRATION (WPO365 | LOGIN) <= 44.1 - Unauthenticated Authentication Bypass via OIDC Nonce Replay via id_token Nonce VerificationUpdated 10 Oct 2026
- WPO365 | SEAMLESS WORDPRESS + MICROSOFT INTEGRATION (WPO365 | LOGIN) <= 44.1 - Missing AuthorizationUpdated 8 Oct 2026
- WPO365 | SEAMLESS WORDPRESS + MICROSOFT INTEGRATION (WPO365 | LOGIN) <= 43.2 - Cross-Site Request Forgery to Privilege Escalation via Plugin Settings UpdateUpdated 23 Jul 2026
- WPO365 <= 40.0 - Authenticated (Subscriber+) Server-Side Request ForgeryUpdated 28 Jan 2026