Description

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.

Severity (CVSS)

Base score9.3
SeverityCritical
VersionCVSS 4.0
VectorCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Provided byCNA

Weaknesses

  • CWE-347 — CWE-347: Improper Verification of Cryptographic Signature

Affected products

VendorProductVersions
microsofto365-moodle< 4.5.6; >= 5.0.0, < 5.0.5; >= 5.1.0, < 5.1.1

References

Authoritative sources

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Generated from the official CVE List on 17 Jul 2026 07:01 UTC.