← Vulnerability feed

Vulnerability record · CVE-2021-36393 · published 6 March 2023

CVE-2021-36393: Moodle SQL injection in recent courses library

Moodle · Moodle

Moodle contains a SQL injection flaw in the library that fetches a user's recent courses. Because the injection point is reachable over the network without authentication, it exposes the database to direct manipulation. The record gives no affected version range, so defenders must confirm their release against the vendor advisory.

9.8 CVSS 3.1 Critical EPSS 52% · top 1.1% CWE-89 · SQL injection
9.8CVSS 3.1 base score
52%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
2References
17 Jun 2026Last modified by NVD

Description

In Moodle, an SQL injection risk was identified in the library fetching a user's recent courses.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Automated analysis

Generated by VULONE's analysis model from the NVD record, CISA KEV and EPSS data on 20 September 2026. Confidence: medium.

critical priorityCVSS 9.8 with no authentication or user interaction required, and a very high EPSS score, make this an urgent patch target despite the absence of KEV listing.

What it is

Moodle contains a SQL injection flaw in the library that fetches a user's recent courses. Because the injection point is reachable over the network without authentication, it exposes the database to direct manipulation. The record gives no affected version range, so defenders must confirm their release against the vendor advisory.

Impact

An unauthenticated attacker can inject SQL into queries run by the recent-courses library, potentially reading, altering, or deleting data in the Moodle database and, depending on database privileges, executing further database-level actions.

Attack surface

Reached over the network via the vulnerable recent-courses code path; the CVSS vector shows no privileges and no user interaction required, so no authentication is needed.

Exploitation

Not listed in CISA KEV and no public exploit reference is tagged, but EPSS is 0.523 (98.9th percentile), indicating a high modeled likelihood of exploitation activity.

What to do

  • Apply the vendor patch referenced in the Moodle advisory (forum discussion 424798) as the first action.
  • If immediate patching is not possible, restrict network access to the affected Moodle endpoints to trusted users or networks.
  • Review database account privileges used by Moodle and remove unnecessary write or administrative rights.
  • Audit and monitor Moodle logs for anomalous requests to recent-course functionality until patched.

Detection

  • Search web and application logs for unusual or malformed requests to recent-course endpoints.
  • Enable and review database query logging for injected SQL patterns originating from Moodle application accounts.
  • Alert on unexpected schema changes, bulk data reads, or errors from the Moodle database user.
  • Correlate Moodle access logs with database activity to spot injection attempts.

This assessment is produced automatically and is not human-reviewed. Verify against the vendor advisory before acting on it.

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://moodle.org/mod/forum/discuss.php?d=424798 PatchVendor Advisory
https://moodle.org/mod/forum/discuss.php?d=424798 PatchVendor Advisory

Track CVE-2021-36393 inside VULONE

Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.

Start free Open in platform

Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

10.0CVE-2019-3809Moodle cross-site request forgery vulnerabilityA flaw was found in Moodle versions 3.1 to 3.1.15 and earlier unsupported versions. The mybackpack functionality allowed setting the URL of badges, w…EPSS 0.86%10.0CVE-2006-4935Moodle improper input validation vulnerabilityThe Database module in Moodle before 1.6.2 does not properly handle uploaded files, which has unspecified impact and remote attack vectors.EPSS 1.5%10.0CVE-2006-4936Moodle improper input validation vulnerabilityMoodle before 1.6.2 does not properly validate the module instance id when creating a course module object, which has unspecified impact and remote a…EPSS 1.5%10.0CVE-2005-2247Moodle vulnerabilityMultiple unknown vulnerabilities in Moodle before 1.5.1 have unknown impact and attack vectors.EPSS 1.5%10.0CVE-2004-2233Moodle vulnerabilityUnknown "front page vulnerability with Moodle servers" for Moodle before 1.3.2 has unknown impact and attack vectors.EPSS 1.7%10.0CVE-2004-2235Moodle vulnerabilityUnknown vulnerability in Moodle before 1.2 has unknown impact and attack vectors, related to improper filtering of text.EPSS 1.4%10.0CVE-2004-2236Moodle vulnerabilityUnknown vulnerability in Moodle before 1.3.3 has unknown impact and attack vectors, related to language setting.EPSS 1.4%10.0CVE-2004-2237Moodle vulnerabilityUnknown vulnerability in Moodle before 1.3.4 has unknown impact and attack vectors, related to "strings in Moodle texts."EPSS 1.7%

Source: NIST National Vulnerability Database (record CVE-2021-36393), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.