Cotonti through 1.0.0 Reflected XSS via message.php lng parameter

{
  "id": "ff1709f27713672cb1419e353fbabfc24430da3811efb4af9cec955e4103d158",
  "url": "https://osv.dev/vulnerability/CVE-2026-100522",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Cotonti through 1.0.0 Reflected XSS via message.php lng parameter",
    "summary": "Cotonti through 1.0.0 contains a reflected cross-site scripting vulnerability in message.php where the lng parameter is not properly escaped before output in the confirmation dialog. Unauthenticated attackers can craft malicious links with script payloads in the lng parameter to execute arbitrary JavaScript in victim browser sessions.",
    "evidence": "osv:CVE-2026-100522",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-100522",
      "aliases": [
        "CVE-2026-100522"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/cotonti/cotonti",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "last_affected": "0d554e939a315e7f7f18fba3ca1132b80c6a1adb"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "last_affected": "1.0.0"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "last_affected": "1.0.0"
                      }
                    ],
                    "source": "DESCRIPTION"
                  }
                ]
              }
            }
          ],
          "versions": [
            "1.0.0",
            "0.9.25",
            "0.9.24.2",
            "0.9.24.1",
            "0.9.24",
            "0.9.23",
            "0.9.22",
            "0.9.21",
            "0.9.20.1",
            "0.9.20",
            "0.9.19",
            "0.9.19-rc1",
            "0.9.19-RC.1",
            "0.9.18.1",
            "0.9.18",
            "0.9.17",
            "0.9.16.2",
            "0.9.16.1",
            "0.9.16",
            "0.9.15",
            "0.9.14",
            "0.9.13",
            "0.9.12.1",
            "0.9.12",
            "cotonti-0.9.11.1",
            "cotonti-0.9.11",
            "cotonti-0.9.10",
            "cotonti-0.9.8",
            "cotonti-0.9.7",
            "cotonti-0.9.6",
            "cotonti-0.9.3"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-100522.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:52.468519035Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/100xxx/CVE-2026-100522.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-100522",
        "https://www.vulncheck.com/advisories/cotonti-through-1.0.0-reflected-xss-via-message-php-lng-parameter",
        "https://github.com/Cotonti/Cotonti/issues/1907",
        "https://github.com/Cotonti/Cotonti/pull/1908",
        "https://github.com/Cotonti/Cotonti",
        "https://github.com/Cotonti/Cotonti/blob/1.0.0/message.php"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-79"
        ],
        "cna_assigner": "VulnCheck",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/100xxx/CVE-2026-100522.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-100522",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 521212,
  "published_at": "2026-09-26T00:59:23.634+00:00"
}