CVE-2026-54733

CRITICAL

moodle-local_o365: Authentication bypass via unverified JWT signature in Teams SSO endpoint

Title source: cna
STIX 2.1

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.

References (7)

Core 7
Core References

Scores

CVSS v4 9.3
EPSS 0.0092
EPSS Percentile 56.6%
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CISA SSVC

Vulnrichment
Exploitation none
Automatable yes
Technical Impact total

Details

CWE
CWE-347
Status published
Products (3)
microsoft/o365-moodle < 4.5.6
microsoft/o365-moodle >= 5.0.0, < 5.0.5
microsoft/o365-moodle >= 5.1.0, < 5.1.1
Published Jul 16, 2026
Tracked Since Jul 16, 2026