CVE-2021-32476: Moodle/moodle Moodle Denial-of-service Risk Vulnerability

HIGH
Advisory Identifier: GHSA-4qxc-qxrp-33cw
CVSS 7.5
CWE-400 CWE-770
Published
Advisory Summary

CVE-2021-32476 is a HIGH (CVSS 7.5) moodle denial-of-service risk vulnerability (CWE-400: Uncontrolled Resource Consumption) affecting Moodle/moodle libraries in the Packagist ecosystem. The issue involves moodle denial-of-service risk in the draft files area. Remediation is available by upgrading affected packages to version 3.10.4, 3.9.7, 3.8.9, 3.5.18.

CVE-2021-32476 at a Glance

CVE Identifier CVE-2021-32476
GHSA Identifier GHSA-4qxc-qxrp-33cw
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-400: Uncontrolled Resource Consumption
Affected Product Moodle/moodle
Package Ecosystem Packagist
Published Date
Last Updated

Security Impact

CVSS: 7.5

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity None (I:N)
Availability High (A:H)

How to Fix CVE-2021-32476

To remediate this vulnerability, upgrade all affected Moodle/moodle dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

moodle/moodle fixed: 3.10.4
Upgrade moodle/moodle to 3.10.4
moodle/moodle fixed: 3.9.7
Upgrade moodle/moodle to 3.9.7
moodle/moodle fixed: 3.8.9
Upgrade moodle/moodle to 3.8.9
moodle/moodle fixed: 3.5.18
Upgrade moodle/moodle to 3.5.18
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release:

inspect dependencies for moodle/moodle

How to Check if You Are Affected

To determine whether your application is affected by CVE-2021-32476, inspect your project dependencies for Moodle/moodle:

inspect dependencies for moodle/moodle

Analyze the terminal output to locate any version of Moodle/moodle in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 3.10.4), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-400: Uncontrolled Resource Consumption, where the product does not properly control the allocation and maintenance of a limited resource. In Moodle/moodle, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

A denial-of-service risk was identified in the draft files area, due to it not respecting user file upload limits. Moodle versions 3.10 to 3.10.3, 3.9 to 3.9.6, 3.8 to 3.8.8, 3.5 to 3.5.17 and earlier unsupported versions are affected.

CVE-2021-32476 Affected Moodle/moodle Versions

4 component(s)
Fixed Versions:
3.10.43.9.73.8.93.5.18
Product / Package Ecosystem Affected Versions Fixed Version
moodle/moodle
Packagist
≥ 3.10
< 3.10.4
3.10.4
moodle/moodle
Packagist
≥ 3.9
< 3.9.7
3.9.7
moodle/moodle
Packagist
≥ 3.8
< 3.8.9
3.8.9
moodle/moodle
Packagist
≥ 3.5.17
< 3.5.18
3.5.18

References

Frequently Asked Questions

What is CVE-2021-32476?
CVE-2021-32476 is a security vulnerability in Moodle/moodle involving Moodle denial-of-service risk in the draft files area under CWE-400: Uncontrolled Resource Consumption.
Which Moodle/moodle versions are affected?
Affected versions include releases prior to 3.10.4, 3.9.7, 3.8.9, 3.5.18 across affected packages: moodle/moodle.
What version fixes CVE-2021-32476?
Upgrading to 3.10.4, 3.9.7, 3.8.9, 3.5.18 (or the latest patched release for your respective branch) resolves the vulnerability.
Is moodle/moodle affected?
Yes, moodle/moodle is affected in releases prior to 3.10.4, 3.9.7, 3.8.9, 3.5.18. Upgrade your dependency to 3.10.4, 3.9.7, 3.8.9, 3.5.18 or later.
What is the CVSS score of CVE-2021-32476?
CVE-2021-32476 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2021-32476?
CVE-2021-32476 is classified under CWE-400: Uncontrolled Resource Consumption (The product does not properly control the allocation and maintenance of a limited resource.).
How can I check Packagist dependencies for CVE-2021-32476?
Run the dependency tree command: 'inspect dependencies for moodle/moodle'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-4qxc-qxrp-33cw",
  "modified" : "2024-04-23T23:39:07Z",
  "published" : "2022-03-12T00:00:33Z",
  "aliases" : [ "CVE-2021-32476" ],
  "summary" : "Moodle denial-of-service risk in the draft files area",
  "details" : "A denial-of-service risk was identified in the draft files area, due to it not respecting user file upload limits. Moodle versions 3.10 to 3.10.3, 3.9 to 3.9.6, 3.8 to 3.8.8, 3.5 to 3.5.17 and earlier unsupported versions are affected.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "moodle/moodle"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "3.10"
      }, {
        "fixed" : "3.10.4"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "moodle/moodle"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "3.9"
      }, {
        "fixed" : "3.9.7"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "moodle/moodle"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "3.8"
      }, {
        "fixed" : "3.8.9"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "moodle/moodle"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "3.5.17"
      }, {
        "fixed" : "3.5.18"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-32476"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/moodle/moodle"
  }, {
    "type" : "WEB",
    "url" : "https://moodle.org/mod/forum/discuss.php?d=422310"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-400", "CWE-770" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2024-04-23T23:39:07Z",
    "nvd_published_at" : "2022-03-11T18:15:00Z"
  }
}