Improper escaping of encrypted topic titles can lead to Cross-site Scripting under non-default site configuration

{
  "id": "9a4e674d14dbca9281fc728ae779081bcde7e9232fe24c208b94ff1cc055dbde",
  "url": "https://osv.dev/vulnerability/CVE-2023-43657",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Improper escaping of encrypted topic titles can lead to Cross-site Scripting under non-default site configuration",
    "summary": "discourse-encrypt is a plugin that provides a secure communication channel through Discourse. Improper escaping of encrypted topic titles could lead to a cross site scripting (XSS) issue when a site has content security policy (CSP) headers disabled. Having CSP disabled is a non-default configuration, and having it disabled with discourse-encrypt installed will result in a warning in the Discourse admin dashboard. This has been fixed in commit `9c75810af9` which is included in the latest version of the discourse-encrypt plugin. Users are advised to upgrade. Users unable to upgrade should ensure that CSP headers are enabled and properly configured.",
    "evidence": "osv:CVE-2023-43657",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2023-43657",
      "aliases": [
        "CVE-2023-43657",
        "GHSA-5fh6-wp7p-xx7v"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/discourse/discourse-encrypt",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "9c75810af9a474d7edaec67dea66f852c0ba1f4e"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "fixed": "9c75810af9a474d7edaec67dea66f852c0ba1f4e"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2023-43657.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:33.166744623Z",
      "provider": "osv",
      "references": [
        "https://developer.mozilla.org/en-US/docs/Web/HTTP/CSP",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/43xxx/CVE-2023-43657.json",
        "https://github.com/discourse/discourse-encrypt/security/advisories/GHSA-5fh6-wp7p-xx7v",
        "https://nvd.nist.gov/vuln/detail/CVE-2023-43657",
        "https://github.com/discourse/discourse-encrypt/commit/9c75810af9a474d7edaec67dea66f852c0ba1f4e"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-79"
        ],
        "cna_assigner": "GitHub_M",
        "unresolved_ranges": [
          {
            "extracted_events": [
              {
                "range": [
                  {
                    "last_affected": "c492904c"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StringRangeExpression"
              }
            ]
          }
        ],
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/43xxx/CVE-2023-43657.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2023-43657",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 500397,
  "published_at": "2023-09-28T18:04:26.672+00:00"
}