CVE-2026-113728 (GCVE-0-2026-113728)

Vulnerability from cvelistv5 – Published: 2026-10-20 21:12 – Updated: 2026-10-20 21:12
VLAI
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.
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CWE
  • CWE-918 - Server-Side Request Forgery (SSRF)
Assigner
GitHub_M CNA under the mitre root
CNA scorecard C 72/100 over 7668 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
bulwarkmail webmail Affected: < 1.9.2
guessed Create a notification for this product.
Show details on NVD website
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{
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      "affected": [
        {
          "product": "webmail",
          "vendor": "bulwarkmail",
          "versions": [
            {
              "status": "affected",
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            }
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          "value": "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."
        }
      ],
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            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-918",
              "description": "CWE-918: Server-Side Request Forgery (SSRF)",
              "lang": "en",
              "type": "CWE"
            }
          ]
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      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-20T21:12:38.182Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/bulwarkmail/webmail/security/advisories/GHSA-24w9-8r42-8jwm",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/bulwarkmail/webmail/security/advisories/GHSA-24w9-8r42-8jwm"
        },
        {
          "name": "https://github.com/bulwarkmail/webmail/commit/3288589e5248dcc1da769cc578827a9ee1adc941",
          "tags": [
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          ],
          "url": "https://github.com/bulwarkmail/webmail/commit/3288589e5248dcc1da769cc578827a9ee1adc941"
        },
        {
          "name": "https://github.com/bulwarkmail/webmail/releases/tag/1.9.2",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/bulwarkmail/webmail/releases/tag/1.9.2"
        }
      ],
      "source": {
        "advisory": "GHSA-24w9-8r42-8jwm",
        "discovery": "UNKNOWN"
      },
      "title": "Bulwark Webmail: DNS-rebinding SSRF in public iCalendar fetch endpoint"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-113728",
    "datePublished": "2026-10-20T21:12:38.182Z",
    "dateReserved": "2026-10-20T16:03:14.864Z",
    "dateUpdated": "2026-10-20T21:12:38.182Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-113728",
      "date": "2026-10-22",
      "epss": "0.00507",
      "percentile": "0.42367"
    },
    "nvd": {
      "cve": {
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          {
            "affectedData": [
              {
                "product": "webmail",
                "vendor": "bulwarkmail",
                "versions": [
                  {
                    "status": "affected",
                    "version": "\u003c 1.9.2"
                  }
                ]
              }
            ],
            "source": "security-advisories@github.com"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "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."
          }
        ],
        "id": "CVE-2026-113728",
        "lastModified": "2026-10-22T16:47:38.403",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "NONE",
                "baseScore": 7.5,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "NONE",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
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              },
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              "impactScore": 3.6,
              "source": "security-advisories@github.com",
              "type": "Secondary"
            }
          ]
        },
        "published": "2026-10-20T22:19:29.740",
        "references": [
          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/bulwarkmail/webmail/commit/3288589e5248dcc1da769cc578827a9ee1adc941"
          },
          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/bulwarkmail/webmail/releases/tag/1.9.2"
          },
          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/bulwarkmail/webmail/security/advisories/GHSA-24w9-8r42-8jwm"
          }
        ],
        "sourceIdentifier": "security-advisories@github.com",
        "vulnStatus": "Awaiting Analysis",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-918"
              }
            ],
            "source": "security-advisories@github.com",
            "type": "Primary"
          }
        ]
      }
    }
  }
}



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