{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "2026.8.0"
              },
              {
                "introduced": "2026.7.0-latest"
              },
              {
                "fixed": "2026.7.2"
              },
              {
                "introduced": "2026.6.0-latest"
              },
              {
                "fixed": "2026.6.3"
              },
              {
                "introduced": "2026.1.0-latest"
              },
              {
                "fixed": "2026.1.8"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "introduced": "ded677e00beb0e9bae6e70b69582aecfb72b5477"
            },
            {
              "introduced": "06d03da34c4ed09ea59f917f045ba250d2b6320d"
            },
            {
              "introduced": "322d3c0ac6a8f133b3f82875e9dbbe310f638c1b"
            },
            {
              "fixed": "fb9247e04a826ab8e4d91168b3c4c839ec40bccc"
            },
            {
              "fixed": "3ab62a8397926ed934b667a5db06284c45b4c774"
            },
            {
              "fixed": "777cb880553b517bc9ae502e935a160332e48b78"
            },
            {
              "fixed": "e808d0853e013abf90e648e53ebd606c49ccb19f"
            },
            {
              "fixed": "042d7b159beda4f74d23e245e8b2e396d9ff8318"
            },
            {
              "fixed": "097ce5600a2d74d9c68e57974597ab2684bd2a24"
            },
            {
              "fixed": "0b5a27e689925edce9ba9b14110022435d2b94be"
            },
            {
              "fixed": "142f5155ad8e56ddb8012c4e70c69a03dedc0579"
            }
          ],
          "repo": "https://github.com/discourse/discourse",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-6pwj-wgg8-4rjc"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-22"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/91xxx/CVE-2026-91123.json"
  },
  "details": "Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, the iframe src traversal guard did not treat literal backslashes as path separators after decoded dot segments. A crafted source could therefore pass an allowed_iframes subpath check while browser URL normalization moved the iframe outside the intended allowed path. The resulting iframe could load content from a location that the administrator did not allow. This issue is fixed in versions 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0.",
  "id": "CVE-2026-91123",
  "modified": "2026-09-26T03:30:58.065128687Z",
  "published": "2026-09-24T16:54:59.357Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/91xxx/CVE-2026-91123.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/discourse/discourse/security/advisories/GHSA-6pwj-wgg8-4rjc"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-91123"
    },
    {
      "type": "FIX",
      "url": "https://github.com/discourse/discourse/commit/042d7b159beda4f74d23e245e8b2e396d9ff8318"
    },
    {
      "type": "FIX",
      "url": "https://github.com/discourse/discourse/commit/097ce5600a2d74d9c68e57974597ab2684bd2a24"
    },
    {
      "type": "FIX",
      "url": "https://github.com/discourse/discourse/commit/0b5a27e689925edce9ba9b14110022435d2b94be"
    },
    {
      "type": "FIX",
      "url": "https://github.com/discourse/discourse/commit/142f5155ad8e56ddb8012c4e70c69a03dedc0579"
    },
    {
      "type": "FIX",
      "url": "https://github.com/discourse/discourse/pull/42882"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Discourse: Reject literal backslash path separators in iframe src traversal guard"
}