Visual editor persistent Cross-site Scripting (XSS) in MyBB

{
  "id": "d643ea9c158727120ff4ff220b1435b702aaadcef44002de1275784bab3c4b76",
  "url": "https://osv.dev/vulnerability/CVE-2023-46251",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Visual editor persistent Cross-site Scripting (XSS) in MyBB",
    "summary": "MyBB is a free and open source forum software. Custom MyCode (BBCode) for the visual editor (_SCEditor_) doesn't escape input properly when rendering HTML, resulting in a DOM-based XSS vulnerability. This weakness can be exploited by pointing a victim to a page where the visual editor is active (e.g. as a post or Private Message) and operates on a maliciously crafted MyCode message. This may occur on pages where message content is pre-filled using a GET/POST parameter, or on reply pages where a previously saved malicious message is quoted. The impact is be mitigated when: 1. the visual editor is disabled globally (_Admin CP → Configuration → Settings → Clickable Smilies and BB Code: [Clickable MyCode Editor](https://github.com/mybb/mybb/blob/mybb_1836/install/resources/settings.xml#L2087-L2094)_ is set to _Off_), or 2. the visual editor is disabled for individual user accounts (_User CP → Your Profile → Edit Options_: _Show the MyCode formatting options on the posting pages_ checkbox is not checked). MyBB 1.8.37 resolves this issue with the commit `6dcaf0b4d`. Users are advised to upgrade. Users unable to upgrade may mitigate the impact without upgrading MyBB by changing the following setting (_Admin CP → Configuration → Settings_): - _Clickable Smilies and BB Code → [Clickable MyCode Editor](https://github.com/mybb/mybb/blob/mybb_1836/install/resources/settings.xml#L2087-L2094)_: _Off_. Similarly, individual MyBB forum users are able to disable the visual editor by diabling ",
    "evidence": "osv:CVE-2023-46251",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2023-46251",
      "aliases": [
        "BIT-mybb-2023-46251",
        "CVE-2023-46251",
        "GHSA-wj33-q7vj-9fr8"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/mybb/mybb",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "6dcaf0b4db6254f1833fe8dae295d9ddc2219276"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "fixed": "6dcaf0b4db6254f1833fe8dae295d9ddc2219276"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "mybb_1837_build",
            "mybb_1836",
            "mybb_1835_build",
            "mybb_1835",
            "mybb_1834",
            "mybb_1834_build",
            "mybb_1833",
            "mybb_1833_build",
            "mybb_1832",
            "mybb_1832_build",
            "mybb_1831",
            "mybb_1831_build",
            "mybb_1829",
            "mybb_1828",
            "mybb_1828_build",
            "mybb_1827_build",
            "mybb_1827",
            "mybb_1823_build",
            "mybb_1823",
            "mybb_1822",
            "mybb_1822_build",
            "mybb_1821pl1",
            "mybb_1821",
            "mybb_1821_build",
            "mybb_1817_build",
            "mybb_1817",
            "mybb_1820",
            "mybb_1820_build",
            "mybb_1820-rc",
            "mybb_1819",
            "mybb_1818",
            "mybb_1819_build",
            "mybb_1818_build",
            "mybb_1816",
            "mybb_1816_build",
            "mybb_1815",
            "mybb_1815_build",
            "mybb_1814",
            "mybb_1813",
            "mybb_1812",
            "mybb_1811",
            "mybb_1810",
            "mybb_1809",
            "mybb_1808",
            "mybb_1807",
            "mybb_1806",
            "mybb_1805",
            "mybb_1804",
            "mybb_1800",
            "mybb_1801"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2023-46251.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:48.664307602Z",
      "provider": "osv",
      "references": [
        "https://mybb.com/versions/1.8.37/",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/46xxx/CVE-2023-46251.json",
        "https://github.com/mybb/mybb/security/advisories/GHSA-wj33-q7vj-9fr8",
        "https://nvd.nist.gov/vuln/detail/CVE-2023-46251",
        "https://github.com/mybb/mybb/commit/6dcaf0b4db6254f1833fe8dae295d9ddc2219276"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-79"
        ],
        "cna_assigner": "GitHub_M",
        "unresolved_ranges": [
          {
            "extracted_events": [
              {
                "range": [
                  {
                    "fixed": "1.8.37"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StringRangeExpression"
              }
            ]
          }
        ],
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/46xxx/CVE-2023-46251.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2023-46251",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 516924,
  "published_at": "2023-11-06T17:41:30.378+00:00"
}