Cypht 2.0.0 through 2.12.2 Stored DOM XSS via externalResources.js

{
  "id": "4df61de791d5940bdb3d9439e5abbfae16ff21a993539c6963108e7f61533661",
  "url": "https://osv.dev/vulnerability/CVE-2026-113583",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Cypht 2.0.0 through 2.12.2 Stored DOM XSS via externalResources.js",
    "summary": "Cypht webmail 2.0.0 through 2.12.2 contains a DOM-based cross-site scripting vulnerability that allows remote attackers to execute arbitrary JavaScript by crafting malicious alt text or URL values in an HTML email's external image tag when ALLOW_EXTERNAL_IMAGE_SOURCES is enabled. Attackers can send a specially crafted email so that when the victim opens it, the externalResources.js code builds the blocked-image notice using innerHTML with decoded email-derived values, triggering script execution in the victim's authenticated session to read mailboxes, send email, or change settings.",
    "evidence": "osv:CVE-2026-113583",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-113583",
      "aliases": [
        "CVE-2026-113583"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/cypht-org/cypht",
              "type": "GIT",
              "events": [
                {
                  "introduced": "492f6346849fb9bc5cdca5fb9cd88ae24c296fd7"
                },
                {
                  "fixed": "4caf0a64a4d4b1b2756ea05e3883aacac16babc2"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "2.0.0"
                      },
                      {
                        "fixed": "2.13.0"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "range": [
                      {
                        "introduced": "2.0.0"
                      },
                      {
                        "last_affected": "2.12.2"
                      }
                    ],
                    "source": "DESCRIPTION"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v2.12.0",
            "v2.11.0",
            "v2.5.0",
            "v2.2.0",
            "v2.1.0",
            "v2.0.1",
            "v2.0.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-113583.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:25.845058761Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/113xxx/CVE-2026-113583.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-113583",
        "https://www.vulncheck.com/advisories/cypht-through-stored-dom-xss-via-externalresources-js",
        "https://github.com/cypht-org/cypht/pull/2118/changes/75d2fb83d228be2aaa37036a11eea68d82122d85",
        "https://github.com/cypht-org/cypht/releases#release-v2.13.0",
        "https://github.com/cypht-org/cypht"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-79"
        ],
        "cna_assigner": "VulnCheck",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/113xxx/CVE-2026-113583.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-113583",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 492552,
  "published_at": "2026-10-20T11:35:29.543+00:00"
}