Discourse: Encode action_code_who in mention URLs

{
  "id": "2b703f0f0300c357f87cd0d2c41a1e7720d4e336b2285b6b6865a677e7fe65e6",
  "url": "https://osv.dev/vulnerability/CVE-2026-91119",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Discourse: Encode action_code_who in mention URLs",
    "summary": "Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, the topic small-action and nested-activity-log components interpolated the free-form action_code_who value into mention-link href attributes without URL encoding. A quote-bearing display name could terminate the intended URL attribute and inject attacker-controlled elements into the trusted rendered markup. Although the visible mention text was escaped, the unencoded path component allowed stored HTML injection when another user viewed the affected topic action or activity log. This issue is fixed in versions 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0.",
    "evidence": "osv:CVE-2026-91119",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-91119",
      "aliases": [
        "BIT-discourse-2026-91119",
        "CVE-2026-91119",
        "GHSA-pv3p-p3m9-v8v3"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/discourse/discourse",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "fb9247e04a826ab8e4d91168b3c4c839ec40bccc"
                },
                {
                  "introduced": "ded677e00beb0e9bae6e70b69582aecfb72b5477"
                },
                {
                  "fixed": "3ab62a8397926ed934b667a5db06284c45b4c774"
                },
                {
                  "introduced": "06d03da34c4ed09ea59f917f045ba250d2b6320d"
                },
                {
                  "fixed": "777cb880553b517bc9ae502e935a160332e48b78"
                },
                {
                  "introduced": "322d3c0ac6a8f133b3f82875e9dbbe310f638c1b"
                },
                {
                  "fixed": "e808d0853e013abf90e648e53ebd606c49ccb19f"
                },
                {
                  "fixed": "20dbf112760eb1d6a58f2e49aeef7546898b6f1c"
                },
                {
                  "fixed": "66653c484cfb91bc346f9a326f6945387f17b035"
                },
                {
                  "fixed": "77a81c7a3a7ff9e94b355e32b8f379f2d389e05a"
                },
                {
                  "fixed": "c4748f651d9d2f3a6dd3106a4d5564536c645168"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "2026.8.0"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "introduced": "2026.7.0-latest"
                      },
                      {
                        "fixed": "2026.7.2"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "introduced": "2026.6.0-latest"
                      },
                      {
                        "fixed": "2026.6.3"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "introduced": "2026.1.0-latest"
                      },
                      {
                        "fixed": "2026.1.8"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "20dbf112760eb1d6a58f2e49aeef7546898b6f1c"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "66653c484cfb91bc346f9a326f6945387f17b035"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "77a81c7a3a7ff9e94b355e32b8f379f2d389e05a"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "c4748f651d9d2f3a6dd3106a4d5564536c645168"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v2026.1.7",
            "v2026.7.1",
            "v2026.6.2",
            "v2026.1.6",
            "v2026.7.0",
            "v2026.6.1",
            "_gh-attach-assets",
            "v2026.1.5",
            "v2026.6.0",
            "v2026.7.0-latest",
            "v2026.6.0-latest",
            "v2026.1.4",
            "v2026.1.3",
            "v2026.1.2",
            "v2026.1.1",
            "v2026.1.0",
            "stable",
            "esr",
            "v2026.1.0-latest"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-91119.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:50.733528722Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/91xxx/CVE-2026-91119.json",
        "https://github.com/discourse/discourse/security/advisories/GHSA-pv3p-p3m9-v8v3",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-91119",
        "https://github.com/discourse/discourse/commit/20dbf112760eb1d6a58f2e49aeef7546898b6f1c",
        "https://github.com/discourse/discourse/commit/66653c484cfb91bc346f9a326f6945387f17b035",
        "https://github.com/discourse/discourse/commit/77a81c7a3a7ff9e94b355e32b8f379f2d389e05a",
        "https://github.com/discourse/discourse/commit/c4748f651d9d2f3a6dd3106a4d5564536c645168",
        "https://github.com/discourse/discourse/pull/42882"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-79"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/91xxx/CVE-2026-91119.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-91119",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 519379,
  "published_at": "2026-09-24T17:07:04.367+00:00"
}