Security advisory

{
  "id": "e55f0b5511973d55230a0f2ad3c56785cc011b99a5c4594f424f01541185ddb7",
  "url": "https://osv.dev/vulnerability/CVE-2021-20185",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2021-20185",
    "summary": "It was found in Moodle before version 3.10.1, 3.9.4, 3.8.7 and 3.5.16 that messaging did not impose a character limit when sending messages, which could result in client-side (browser) denial of service for users receiving very large messages.",
    "evidence": "osv:CVE-2021-20185",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2021-20185",
      "aliases": [
        "BIT-moodle-2021-20185",
        "CVE-2021-20185",
        "GHSA-c3j6-33r4-89q3"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/moodle/moodle",
              "type": "GIT",
              "events": [
                {
                  "introduced": "46574904afd39578fa4146bf1fc5c401ac680aa6"
                },
                {
                  "fixed": "bbf242efb086307a0af9367d6caea08649b261d1"
                },
                {
                  "introduced": "f968cd44e8ee5d54b1bc56823040ff770dbf18af"
                },
                {
                  "fixed": "323c12674aa74d327ded9f5e44458cd5d1aea174"
                },
                {
                  "introduced": "500c131eb49771e36f68d151dfa37fef5a9bc2df"
                },
                {
                  "fixed": "de301d4237c42ddd0d4ae7395e663b8457943727"
                },
                {
                  "introduced": "ec58cefefb2722f61f77c9a2b6a12d40a8c078a0"
                },
                {
                  "last_affected": "ec58cefefb2722f61f77c9a2b6a12d40a8c078a0"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:moodle:moodle:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "3.5.0"
                      },
                      {
                        "fixed": "3.5.16"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "cpe": "cpe:2.3:a:moodle:moodle:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "3.8.0"
                      },
                      {
                        "fixed": "3.8.7"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "cpe": "cpe:2.3:a:moodle:moodle:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "3.9.0"
                      },
                      {
                        "fixed": "3.9.4"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "cpe": "cpe:2.3:a:moodle:moodle:3.10.0:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "3.10.0"
                      },
                      {
                        "last_affected": "3.10.0"
                      }
                    ],
                    "source": "CPE_STRING"
                  }
                ]
              }
            }
          ],
          "versions": [
            "3.10.0",
            "v3.9.3",
            "v3.5.15",
            "v3.8.6",
            "v3.10.0",
            "v3.9.2",
            "v3.8.5",
            "v3.5.14",
            "v3.5.13",
            "v3.8.4",
            "v3.9.1",
            "v3.9.0",
            "v3.8.3",
            "v3.5.12",
            "v3.8.2",
            "v3.5.11",
            "v3.5.10",
            "v3.8.1",
            "v3.8.0",
            "v3.5.9",
            "v3.5.8",
            "v3.5.7",
            "v3.5.6",
            "v3.5.5",
            "v3.5.4",
            "v3.5.3",
            "v3.5.2",
            "v3.5.1",
            "v3.5.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-20185.json"
          }
        }
      ],
      "modified": "2026-10-24T10:30:25.623295162Z",
      "provider": "osv",
      "references": [
        "https://moodle.org/mod/forum/discuss.php?d=417168"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2021-20185",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 431402,
  "published_at": "2021-01-28T20:15:13.133+00:00"
}