Moodle: reflected xss risk in some returnurl parameters

{
  "id": "f8395e4b2fe2dd658bef3b56123631063835b62bb72cca4ec4bf0cf808ec634c",
  "url": "https://osv.dev/vulnerability/CVE-2023-23921",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Moodle: reflected xss risk in some returnurl parameters",
    "summary": "The vulnerability was found Moodle which exists due to insufficient sanitization of user-supplied data in some returnurl parameters. A remote attacker can trick the victim to follow a specially crafted link and execute arbitrary HTML and script code in user's browser in context of vulnerable website. This flaw allows a remote attacker to perform cross-site scripting (XSS) attacks.",
    "evidence": "osv:CVE-2023-23921",
    "products": [],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2023-23921",
      "aliases": [
        "BIT-moodle-2023-23921",
        "CVE-2023-23921",
        "GHSA-97qf-pq7x-964m"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/moodle/moodle",
              "type": "GIT",
              "events": [
                {
                  "introduced": "500c131eb49771e36f68d151dfa37fef5a9bc2df"
                },
                {
                  "fixed": "fc01a52823ce31d57c2964daf3ead094869dd016"
                },
                {
                  "introduced": "94f2d3fc4b974c5c7d500988c56b7ca15f58d7ec"
                },
                {
                  "fixed": "f21e1443dc0cd26891becf3aa5bea735211dd8a8"
                },
                {
                  "introduced": "8b359ad7a63cf219110bca80552fe3d4ea2a635d"
                },
                {
                  "fixed": "b864c78a31e0b2c245e2cf4ff6a566be435fec3a"
                },
                {
                  "introduced": "0ea3d45e04c3d54a3a472ddcb11606b30e227c50"
                },
                {
                  "last_affected": "0ea3d45e04c3d54a3a472ddcb11606b30e227c50"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:moodle:moodle:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "3.9.0"
                      },
                      {
                        "fixed": "3.9.19"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "cpe": "cpe:2.3:a:moodle:moodle:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "3.11.0"
                      },
                      {
                        "fixed": "3.11.12"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "cpe": "cpe:2.3:a:moodle:moodle:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "4.0.0"
                      },
                      {
                        "fixed": "4.0.6"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "cpe": "cpe:2.3:a:moodle:moodle:4.1.0:-:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "4.1.0-NA"
                      },
                      {
                        "last_affected": "4.1.0-NA"
                      }
                    ],
                    "source": "CPE_STRING"
                  }
                ]
              }
            }
          ],
          "versions": [
            "4.1.0-NA",
            "v4.1.0",
            "v3.9.18",
            "v3.11.11",
            "v4.0.5",
            "v3.11.10",
            "v3.9.17",
            "v4.0.4",
            "v3.9.16",
            "v3.11.9",
            "v4.0.3",
            "v4.0.2",
            "v3.11.8",
            "v3.9.15",
            "v3.9.14",
            "v4.0.1",
            "v3.11.7",
            "v4.0.0",
            "v3.11.6",
            "v3.9.13",
            "v3.11.5",
            "v3.9.12",
            "v3.11.4",
            "v3.9.11",
            "v3.11.3",
            "v3.9.10",
            "v3.11.1",
            "v3.11.2",
            "v3.9.9",
            "v3.9.8",
            "v3.11.0",
            "v3.9.7",
            "v3.9.6",
            "v3.9.5",
            "v3.9.4",
            "v3.9.3",
            "v3.9.2",
            "v3.9.1",
            "v3.9.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2023-23921.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:50.811742441Z",
      "provider": "osv",
      "references": [
        "https://git.moodle.org",
        "https://moodle.org/mod/forum/discuss.php?d=443272#p1782021",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/23xxx/CVE-2023-23921.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2023-23921",
        "https://bugzilla.redhat.com/show_bug.cgi?id=2162526"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-79"
        ],
        "cna_assigner": "fedora",
        "unresolved_ranges": [
          {
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "4.1.0"
                  },
                  {
                    "fixed": "4.1.1"
                  },
                  {
                    "introduced": "4.0.0"
                  },
                  {
                    "fixed": "4.0.6"
                  },
                  {
                    "introduced": "3.11.0"
                  },
                  {
                    "fixed": "3.11.12"
                  },
                  {
                    "fixed": "3.9.19"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StandardRange"
              }
            ]
          }
        ],
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/23xxx/CVE-2023-23921.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2023-23921",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 519496,
  "published_at": "2023-02-17T00:00:00+00:00"
}