CVE-2026-54733
moodle-local_o365: Authentication bypass via unverified JWT signature in Teams SSO endpoint
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.
INFO
Published Date :
July 16, 2026, 4:19 p.m.
Last Modified :
July 16, 2026, 4:19 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-54733
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 4.0 | CRITICAL | [email protected] |
Solution
- Update the Microsoft Office 365 Integration plugin.
- Apply updates to versions 4.5.6, 5.0.5, or 5.1.1.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-54733.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-54733 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-54733
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-54733 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-54733 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Jul. 16, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'microsoft', 'product': 'o365-moodle', 'versions': [{'status': 'affected', 'version': '< 4.5.6'}, {'status': 'affected', 'version': '>= 5.0.0, < 5.0.5'}, {'status': 'affected', 'version': '>= 5.1.0, < 5.1.1'}]}] Added 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. Added CVSS V4.0 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 Added CWE CWE-347 Added Reference https://github.com/microsoft/o365-moodle/commit/01b2d4c2e13b06a66557527084cbf9bace655944 Added Reference https://github.com/microsoft/o365-moodle/commit/258872f6e2011f4efa8ebb77d2898142a9435e89 Added Reference https://github.com/microsoft/o365-moodle/commit/d5596655f0baaee0f11aec2e10d6f36b0bd29220 Added Reference https://github.com/microsoft/o365-moodle/releases/tag/v20260423_m405 Added Reference https://github.com/microsoft/o365-moodle/releases/tag/v20260423_m500 Added Reference https://github.com/microsoft/o365-moodle/releases/tag/v20260423_m501 Added Reference https://github.com/microsoft/o365-moodle/security/advisories/GHSA-hqjh-93qv-47v5 -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jul. 16, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-54733', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'yes'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-07-16T15:34:47.399720Z'}