PatchSiren cyber security CVE debrief
CVE-2026-54733 microsoft CVE debrief
The Microsoft 365 and Microsoft Entra ID Plugins for Moodle provide Office 365 and Azure Active Directory integration for Moodle. Prior to 4.5.6, 5.0.5, and 5.1.1, the Microsoft Office 365 Integration plugin local_o365 Teams SSO endpoint sso_login.php base64-decodes a JWT payload and authenticates users from the upn claim without verifying the JWT signature, allowing an unauthenticated attacker to forge a token and obtain a Moodle session as an O365-authenticated user. This issue is fixed in versions 4.5.6, 5.0.5, and 5.1.1. Moodle users with Microsoft 365 and Microsoft Entra ID Plugins installed should verify their plugin versions and update to 4.5.6, 5.0.5, or 5.1.1 to mitigate this critical vulnerability.
- Vendor
- microsoft
- Product
- o365-moodle
- CVSS
- CRITICAL 9.3
- CISA KEV
- Not listed in stored evidence
- Original CVE published
- 2026-07-16
- Original CVE updated
- 2026-07-16
- Advisory published
- 2026-07-16
- Advisory updated
- 2026-07-16
Who should care
Moodle users with Microsoft 365 and Microsoft Entra ID Plugins installed should verify their plugin versions and update to 4.5.6, 5.0.5, or 5.1.1 to mitigate this critical vulnerability. This vulnerability affects Moodle users with Microsoft 365 and Microsoft Entra ID Plugins installed, and defenders should review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance.
Technical summary
The Microsoft Office 365 Integration plugin for Moodle has a critical vulnerability (CVSS Score: 9.3) that allows an unauthenticated attacker to forge a token and obtain a Moodle session as an O365-authenticated user. This is due to the local_o365 Teams SSO endpoint sso_login.php base64-decoding a JWT payload and authenticating users from the upn claim without verifying the JWT signature. The vulnerability affects Moodle users with Microsoft 365 and Microsoft Entra ID Plugins installed.
Defensive priority
High
Recommended defensive actions
- Update Microsoft 365 and Microsoft Entra ID Plugins for Moodle to version 4.5.6, 5.0.5, or 5.1.1
- Verify plugin versions and configurations
- Monitor for suspicious activity
- Review compensating controls for exposed systems while remediation is scheduled and verified
- Check relevant monitoring, detection, and logs for exposed assets that need extra review
- Track exceptions, retest remediated assets, and close the item only after evidence is documented
- Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
Evidence notes
The CVE record was published on 2026-07-16T16:19:13.360Z and was last modified on 2026-07-16T17:46:34.020Z. The NVD entry is currently Awaiting Analysis. There is limited information available about the vulnerability, and defenders should verify the affected scope and severity with the vendor. The Microsoft Office 365 Integration plugin for Moodle has a critical vulnerability that allows an unauthenticated attacker to forge a token and obtain a Moodle session as an O365-authenticated user.
Official resources
AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-07-16T16:19:13.360Z and has not been modified since then. The NVD entry is currently Awaiting Analysis.