Bulwark Webmail: DNS-rebinding SSRF in public iCalendar fetch endpoint

{
  "id": "84375be5b5b6d6a042d26e20f2a00d6d0ab0ba9bd21895eaace90a4d7d3836c7",
  "url": "https://www.cve.org/CVERecord?id=CVE-2026-113728",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Bulwark Webmail: DNS-rebinding SSRF in public iCalendar fetch endpoint",
    "summary": "Bulwark Webmail is a self-hosted webmail client for Stalwart Mail Server. Prior to 1.9.2, the unauthenticated POST /api/fetch-ical endpoint validates a caller-supplied hostname with one DNS lookup and then passes the URL to fetch, which performs a separate lookup for the socket connection. An attacker controlling authoritative DNS can return a public address during validation and then rebind the hostname to a loopback, private, link-local, or cloud metadata address for the connection, causing the server to return up to 10 MB of an internal HTTP or HTTPS response. The same check-then-fetch pattern also existed in authenticated JMAP login and TOTP token-exchange flows. This issue is fixed in version 1.9.2.",
    "evidence": "cve:CVE-2026-113728",
    "products": [
      {
        "name": {
          "value": "webmail",
          "evidence": "/containers/cna/affected/0/product"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-113728",
      "aliases": [
        "CVE-2026-113728"
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "scope": "UNCHANGED",
            "version": "3.1",
            "baseScore": 7.5,
            "attackVector": "NETWORK",
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
            "integrityImpact": "NONE",
            "userInteraction": "NONE",
            "attackComplexity": "LOW",
            "availabilityImpact": "NONE",
            "privilegesRequired": "NONE",
            "confidentialityImpact": "HIGH"
          }
        }
      ],
      "affected": [
        {
          "vendor": "bulwarkmail",
          "product": "webmail",
          "versions": [
            {
              "status": "affected",
              "version": "< 1.9.2"
            }
          ]
        }
      ],
      "modified": "2026-10-27T13:28:01.863Z",
      "provider": "cve",
      "references": [
        "https://github.com/bulwarkmail/webmail/security/advisories/GHSA-24w9-8r42-8jwm",
        "https://github.com/bulwarkmail/webmail/commit/3288589e5248dcc1da769cc578827a9ee1adc941",
        "https://github.com/bulwarkmail/webmail/releases/tag/1.9.2"
      ],
      "provider_metadata": {
        "adp": [
          {
            "title": "CISA ADP Vulnrichment",
            "metrics": [
              {
                "other": {
                  "type": "ssvc",
                  "content": {
                    "id": "CVE-2026-113728",
                    "role": "CISA Coordinator",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "yes"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "version": "2.0.3",
                    "timestamp": "2026-10-27T13:27:53.414451Z"
                  }
                }
              }
            ],
            "providerMetadata": {
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP",
              "dateUpdated": "2026-10-27T13:28:01.863Z"
            }
          }
        ],
        "cna": {
          "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
          "shortName": "GitHub_M",
          "dateUpdated": "2026-10-20T21:12:38.182Z"
        }
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-113728",
        "evidence": "/cveMetadata/cveId"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/containers/cna/metrics"
  },
  "source_id": "core-cve",
  "document_id": 392602,
  "published_at": "2026-10-20T21:12:38.182+00:00"
}