Mailpit: WebSocket origin check bypass via percent-encoded path (regression of CVE-2026-22689)

{
  "id": "0aca6d87c3ce7b2d636c844006ed930cfb473311afdc1d0d4795247e67a62014",
  "url": "https://osv.dev/vulnerability/CVE-2026-67448",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Mailpit: WebSocket origin check bypass via percent-encoded path (regression of CVE-2026-22689)",
    "summary": "Mailpit is an email testing tool and API for developers. From 1.29.0 until 1.30.6, Mailpit's server/server.go origin middleware checks the raw RequestURI for the /api/ prefix while Go's ServeMux routes using the percent-decoded URL path, and server/websockets/client.go configures websocket.Upgrader.CheckOrigin to return true. A malicious website can request /%61pi/events, skip corsOriginAccessControl(), reach the /api/events WebSocket handler, and receive live message IDs, Message-Id values, sender and recipient fields, subjects, tags, and body snippets from an unauthenticated default Mailpit instance after the user visits the site. This is a regression of the earlier WebSocket origin protection and does not affect deployments protected by --ui-auth-file. This issue is fixed in version 1.30.6.",
    "evidence": "osv:CVE-2026-67448",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-67448",
      "aliases": [
        "CVE-2026-67448",
        "GHSA-8r62-w5wh-fc5m",
        "GO-2026-6271"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/axllent/mailpit",
              "type": "GIT",
              "events": [
                {
                  "introduced": "43b8ba3dc6c16bd3b10fc40416c8920a85feeb3b"
                },
                {
                  "fixed": "a58a22122eb5259b24e34bd33b7274d046606364"
                },
                {
                  "fixed": "fbe5e006c3f1682b819df58b4a932d7a84920be9"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "1.29.0"
                      },
                      {
                        "fixed": "1.30.6"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "fbe5e006c3f1682b819df58b4a932d7a84920be9"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "a58a22122eb5259b24e34bd33b7274d046606364"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v1.30.6"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v1.30.5",
            "v1.30.4",
            "v1.30.3",
            "v1.30.2",
            "v1.30.1",
            "v1.30.0",
            "v1.29.7",
            "v1.29.6",
            "v1.29.5",
            "v1.29.4",
            "v1.29.3",
            "v1.29.2",
            "v1.29.1",
            "v1.29.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-67448.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:26.787342012Z",
      "provider": "osv",
      "references": [
        "https://github.com/axllent/mailpit/releases/tag/v1.30.6",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/67xxx/CVE-2026-67448.json",
        "https://github.com/axllent/mailpit/security/advisories/GHSA-8r62-w5wh-fc5m",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-67448",
        "https://github.com/axllent/mailpit/commit/fbe5e006c3f1682b819df58b4a932d7a84920be9"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-177",
          "CWE-200",
          "CWE-346"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/67xxx/CVE-2026-67448.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-67448",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 493512,
  "published_at": "2026-08-20T21:29:06.185+00:00"
}