CVE-2025-67848: 
PHP vulnerability analysis and mitigation

CVE-2025-67848 is an authentication bypass vulnerability in Moodle's Learning Tools Interoperability (LTI) Provider that allows suspended users to authenticate and gain unauthorized access to the system. The flaw was reported internally on December 19, 2025, and publicly disclosed on February 3, 2026. It affects Moodle versions prior to 4.1.22, 4.4.0–4.4.11, 4.5.0–4.5.7, 5.0.0–5.0.3, and 5.1.0 (fixed in 4.1.22, 4.4.12, 4.5.8, 5.0.4, and 5.1.1). The vulnerability carries a CVSS v3.1 base score of 8.1 (High) (Github Advisory, Red Hat Bugzilla).

The root cause is classified as CWE-280 (Improper Handling of Insufficient Permissions or Privileges): the LTI authentication handlers in Moodle fail to check whether a user account is in a suspended state before completing authentication. When a suspended user initiates an LTI-based login flow, the handler proceeds without enforcing the suspension flag, effectively bypassing the access restriction. Exploitation requires only low-level (previously valid) credentials and is performed remotely over the network with no user interaction required. Patch commits 62f372e and c2705e2 in the moodle/moodle repository address the missing suspension-status enforcement (Github Advisory, Red Hat Bugzilla).

Successful exploitation allows a suspended (and therefore unauthorized) user to regain access to a Moodle instance, resulting in high confidentiality and high integrity impact with no availability impact. An attacker can access sensitive course content, student data, grades, and personal information, and may also be able to modify records or perform administrative actions depending on the role the suspended account previously held. The scope is limited to the affected Moodle instance, but the data exposure risk is significant in educational environments where personally identifiable information (PII) is routinely stored (Github Advisory, Feedly).

There is no public proof-of-concept exploit and no evidence of in-the-wild exploitation at this time. The EPSS score is approximately 0.048% (15th percentile), indicating a low near-term exploitation probability. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog. No threat actor attribution has been reported (Github Advisory, Feedly).

1. Reconnaissance: Identify a target Moodle instance running a vulnerable version (< 4.1.22, 4.4.0–4.4.11, 4.5.0–4.5.7, 5.0.0–5.0.3, or 5.1.0) using version disclosure on the login page or Shodan/Censys searches for Moodle deployments.
2. Obtain suspended account credentials: Use previously known credentials for an account that has been suspended (e.g., a former student or staff member whose account was deactivated).
3. Initiate LTI authentication flow: Access an LTI-enabled tool or external application linked to the target Moodle instance and trigger the LTI Provider login flow, which redirects authentication handling to Moodle's LTI handler.
4. Bypass suspension check: Because the LTI authentication handler does not enforce the user's suspension status, the login proceeds successfully despite the account being suspended.
5. Gain unauthorized access: The attacker is authenticated into the Moodle session with the permissions of the suspended account, enabling access to course content, user data, and potentially administrative functions depending on the account's prior role (Github Advisory, Red Hat Bugzilla).

• Logs: Moodle access logs showing successful LTI-based authentication events for user accounts that are marked as suspended in the Moodle user database; look for logstore_standard_log entries with action=loggedin and component=mod_lti for suspended user IDs.
• Logs: Unexpected session creation records in Moodle's mdl_sessions table for user accounts with suspended=1 in mdl_user.
• Network: LTI OAuth or OIDC callback requests to /mod/lti/ or /enrol/lti/ endpoints originating from external LTI tool providers, followed by authenticated activity from accounts that should be inactive.
• Application: Audit trail entries in Moodle's site administration logs showing data access, grade modifications, or course enrollment changes attributed to suspended user accounts (Github Advisory).

Moodle has released patched versions: 4.1.22, 4.4.12, 4.5.8, 5.0.4, and 5.1.1. Administrators should upgrade to the appropriate patched release immediately. As a temporary workaround prior to patching, administrators can disable LTI Provider functionality in Moodle site settings to prevent the vulnerable authentication path from being used. Additionally, conducting an audit of suspended user accounts for any recent login activity is recommended to identify potential unauthorized access (Github Advisory, Moodle Forum).

The vulnerability was noted in a CISA weekly vulnerability bulletin (week of February 2, 2026) and referenced by Red Hat's Product Security team via Bugzilla and their CVE portal. A Mastodon post from @thehackerwire briefly highlighted the disclosure. No significant independent researcher commentary or major media coverage has been identified beyond standard vulnerability aggregator coverage (CISA Bulletin, Red Hat Bugzilla).