CVE-2026-54733 (GCVE-0-2026-54733)
Vulnerability from cvelistv5 – Published: 2026-07-16 14:52 – Updated: 2026-07-16 15:35
VLAI
EPSS
VEX
Title
moodle-local_o365: Authentication bypass via unverified JWT signature in Teams SSO endpoint
Summary
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
SSVC
Exploitation: none
Automatable: yes
Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-07-16 15:34 UTC
CWE
- CWE-347 - Improper Verification of Cryptographic Signature
Assigner
References
7 references
| URL | Tags |
|---|---|
| https://github.com/microsoft/o365-moodle/security… | x_refsource_CONFIRM |
| https://github.com/microsoft/o365-moodle/commit/0… | x_refsource_MISC |
| https://github.com/microsoft/o365-moodle/commit/2… | x_refsource_MISC |
| https://github.com/microsoft/o365-moodle/commit/d… | x_refsource_MISC |
| https://github.com/microsoft/o365-moodle/releases… | x_refsource_MISC |
| https://github.com/microsoft/o365-moodle/releases… | x_refsource_MISC |
| https://github.com/microsoft/o365-moodle/releases… | x_refsource_MISC |
Impacted products
1 product
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| microsoft | o365-moodle |
Affected:
< 4.5.6
Affected: >= 5.0.0, < 5.0.5 Affected: >= 5.1.0, < 5.1.1 |
guessed |
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