Security advisory

{
  "id": "481893ec60215d4b7fb6177904bdcacf839a0a12669c07b6437959c6d7b0d92a",
  "url": "https://osv.dev/vulnerability/CVE-2021-3767",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2021-3767",
    "summary": "bookstack is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')",
    "evidence": "osv:CVE-2021-3767",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2021-3767",
      "aliases": [
        "CVE-2021-3767"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/bookstackapp/bookstack",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "88bcb68fcb9ef64af5451dc64d53a7af84454d96"
                },
                {
                  "fixed": "040997fdc4414776bcac06a3cbaac3b26b5e8a64"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:bookstackapp:bookstack:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "21.08.2"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "040997fdc4414776bcac06a3cbaac3b26b5e8a64"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v21.08.1",
            "v21.08",
            "v21.05.4",
            "v21.05.3",
            "v21.05.2",
            "v21.05.1",
            "v21.05",
            "v21.04.6",
            "v21.04.5",
            "v21.04.4",
            "v21.04.3",
            "v21.04.2",
            "v21.04.1",
            "v21.04",
            "v0.31.8",
            "v0.31.7",
            "v0.31.6",
            "v0.31.5",
            "v0.31.4",
            "v0.31.3",
            "v0.31.2",
            "v0.31.1",
            "v0.31.0",
            "v0.30.7",
            "v0.30.6",
            "v0.30.5",
            "v0.30.4",
            "v0.30.3",
            "v0.30.2",
            "v0.30.1",
            "v0.30.0",
            "v0.29.3",
            "v0.29.2",
            "v0.29.1",
            "v0.29.0",
            "v0.28.3",
            "v0.28.2",
            "v0.28.1",
            "v0.28.0",
            "v0.27.5",
            "v0.27.4",
            "v0.27.3",
            "v0.27.2",
            "v0.27.1",
            "v0.27",
            "v0.26.4",
            "v0.26.3",
            "v0.26.2",
            "v0.26.1",
            "v0.26.0",
            "v0.25.5",
            "v0.25.4",
            "v0.25.3",
            "v0.25.2",
            "v0.25.1",
            "v0.25.0",
            "v0.24.3",
            "v0.24.2",
            "v0.24.1",
            "v0.24.0",
            "v0.23.2",
            "v0.23.1",
            "v0.23.0",
            "v0.22.0",
            "v0.21.0",
            "v0.20.3",
            "v0.20.2",
            "v0.20.1",
            "v0.20.0",
            "v0.19.0",
            "v0.18.5",
            "v0.18.4",
            "v0.18.3",
            "v0.18.2",
            "v0.18.1",
            "v0.18.0",
            "v0.17.4",
            "v0.17.3",
            "v0.17.2",
            "v0.17.1",
            "v0.17.0",
            "v0.16.3",
            "v0.16.2",
            "v0.16.1",
            "v0.16.0",
            "v0.15.3",
            "v0.15.2",
            "v0.15.1",
            "v0.15.0",
            "v0.14.3",
            "v0.14.2",
            "v0.14.1",
            "v0.14.0",
            "v0.13.1",
            "v0.13.0",
            "v0.12.2",
            "v0.12.1",
            "v0.12.0",
            "v0.11.2",
            "v0.11.1",
            "v0.11.0",
            "v0.10.0",
            "v0.9.3",
            "v0.9.2",
            "v0.9.1",
            "v0.9.0",
            "v0.8.2",
            "v0.8.1",
            "v0.8.0",
            "v0.7.6",
            "v0.7.5",
            "v0.7.4",
            "v0.7.3",
            "0.7.2",
            "v.0.7.1",
            "v0.7.0",
            "v0.6.3",
            "v0.6.2",
            "v0.6.1",
            "v0.6.0",
            "v0.5.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-3767.json"
          }
        }
      ],
      "modified": "2026-10-20T10:54:49.875992874Z",
      "provider": "osv",
      "references": [
        "https://github.com/bookstackapp/bookstack/commit/040997fdc4414776bcac06a3cbaac3b26b5e8a64",
        "https://huntr.dev/bounties/7ec92c85-30eb-4071-8891-6183446ca980"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2021-3767",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 386234,
  "published_at": "2021-09-06T12:15:08.237+00:00"
}