CVE-2026-54733
SSO token forgery in Moodle Microsoft 365 plugin allows user impersonation
Is CVE-2026-54733 being exploited?
Not confirmed. CVE-2026-54733 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.88% probability of exploitation in the next 30 days.
How severe is CVE-2026-54733?
CVE-2026-54733 is rated Critical with a CVSS score of 9.3. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-54733?
Yes. A fix has been recorded for CVE-2026-54733. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-54733 affect?
CVE-2026-54733 affects Moodle Microsoft 365 / Entra ID Integration plugin (local_o365) <4.5.6, <5.0.5, <5.1.1, Moodle instances using Microsoft Office365 SSO. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-54733?
Upgrade to 4.5.6 / 5.0.5 / 5.1.1 or disable Microsoft 365 SSO until patched.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
JWT signature not verified; attacker can forge tokens to impersonate O365 users and obtain active Moodle sessions.
Immediate action required
- affected< 4.5.6
- affected>= 5.0.0 and < 5.0.5
- affected>= 5.1.0 and < 5.1.1
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.