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CVE

CVE-2026-54733

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

CVE-2026-54733

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

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 localo365 Teams SSO endpoint ssologin.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.

Package Versions Affected

Package Version
patch Availability
No items found.

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CVSS Version

Severity
Base Score
CVSS Version
Score Vector
C
H
U
9.3
-
4.0
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
C
H
U
0
-
C
H
U
-

Related Resources

No items found.

References

https://github.com/microsoft/o365-moodle/releases/tag/v20260423m405, https://github.com/microsoft/o365-moodle/releases/tag/v20260423m500, https://github.com/microsoft/o365-moodle/releases/tag/v20260423_m501, https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/54xxx/CVE-2026-54733.json, https://github.com/microsoft/o365-moodle/security/advisories/GHSA-hqjh-93qv-47v5, https://nvd.nist.gov/vuln/detail/CVE-2026-54733, https://github.com/microsoft/o365-moodle/commit/01b2d4c2e13b06a66557527084cbf9bace655944, https://github.com/microsoft/o365-moodle/commit/258872f6e2011f4efa8ebb77d2898142a9435e89, https://github.com/microsoft/o365-moodle/commit/d5596655f0baaee0f11aec2e10d6f36b0bd29220

Severity

0

CVSS Score
0
10

Basic Information

Base CVSS
0
EPSS Probability
0.00875%
EPSS Percentile
0.56448%
Introduced Version
da127bc48f31dfdb659d5fe0e670e51f386ae3f6
Fix Available
d5596655f0baaee0f11aec2e10d6f36b0bd29220

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