WhatsApp MCP: Unauthenticated bridge API allows message sending and arbitrary file exfiltration

{
  "id": "5b2cf270a503d85be66dc15ec67fc0d98a730b782c338c7dc67435ca6b6e24e0",
  "url": "https://osv.dev/vulnerability/CVE-2026-46555",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "WhatsApp MCP: Unauthenticated bridge API allows message sending and arbitrary file exfiltration",
    "summary": "WhatsApp MCP Server is a Model Context Protocol (MCP) server for WhatsApp, enabling Claude to read and send WhatsApp messages. Prior to version 0.2.1, the `whatsapp-bridge` HTTP API listens on `127.0.0.1:8080` without authentication and without Host header validation, and the `/api/send` endpoint accepts an absolute `media_path` parameter without confining it to a safe directory. Combined, these issues allow any local process running as the same user as the bridge to send WhatsApp messages from the paired account without authorization; the same caller to read arbitrary files readable by the user (e.g. SSH private keys, browser session data, source code, dotfiles) and exfiltrate them as WhatsApp document attachments; and/or a remote attacker to trigger the same operations via DNS rebinding from a webpage the user visits, since no Host header validation is performed. In MCP environments, \"local caller\" extends beyond processes the user explicitly launched — sibling MCP servers, IDE extensions, and tool-triggered flows running in the user's session can act as the effective caller. This issue is fixed in whatsapp-mcp v0.2.1 and corresponding Docker images / release artifacts. Users should upgrade immediately. The fix introduces bearer token authentication on the bridge HTTP API (configured via environment variable, required on all requests, validated with constant-time comparison); host header allow-list validation to prevent DNS rebinding; and confinement of `media_path` to a co",
    "evidence": "osv:CVE-2026-46555",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-46555",
      "aliases": [
        "CVE-2026-46555",
        "GHSA-7jj9-4qqq-4xc4"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/verygoodplugins/whatsapp-mcp",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "6bb5359e8ee68e3285745c8bb86d6c9be88ae2b1"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "0.2.1"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "6bb5359e8ee68e3285745c8bb86d6c9be88ae2b1"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v0.2.1"
                  },
                  {
                    "cpe": "cpe:2.3:a:verygoodplugins:whatsapp_mcp_server:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "0.2.1"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v0.2.0",
            "v0.1.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-46555.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:25.018947343Z",
      "provider": "osv",
      "references": [
        "https://github.com/verygoodplugins/whatsapp-mcp/blob/main/SECURITY.md",
        "https://github.com/verygoodplugins/whatsapp-mcp/releases/tag/v0.2.1",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/46xxx/CVE-2026-46555.json",
        "https://github.com/verygoodplugins/whatsapp-mcp/security/advisories/GHSA-7jj9-4qqq-4xc4",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-46555"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-22",
          "CWE-306",
          "CWE-346"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/46xxx/CVE-2026-46555.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-46555",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 491659,
  "published_at": "2026-07-20T17:06:22.232+00:00"
}