CVE-2026-54733: critical vulnerability in microsoft o365-moodle
moodle-local_o365: Authentication bypass via unverified JWT signature in Teams SSO endpoint
Published
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28Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 9.3epss 0.9%
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.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Affected products
microsoft · o365-moodleReferences
https://github.com/microsoft/o365-moodle/commit/01b2d4c2e13b06a66557527084cbf9bace655944https://github.com/microsoft/o365-moodle/commit/258872f6e2011f4efa8ebb77d2898142a9435e89https://github.com/microsoft/o365-moodle/commit/d5596655f0baaee0f11aec2e10d6f36b0bd29220https://github.com/microsoft/o365-moodle/releases/tag/v20260423_m405https://github.com/microsoft/o365-moodle/releases/tag/v20260423_m500https://github.com/microsoft/o365-moodle/releases/tag/v20260423_m501https://github.com/microsoft/o365-moodle/security/advisories/GHSA-hqjh-93qv-47v5