{"id":"CVE-2026-46555","summary":"WhatsApp MCP: Unauthenticated bridge API allows message sending and arbitrary file exfiltration","details":"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 configured directory, with rejection of absolute paths outside the root and path traversal sequences. This is a breaking change for clients of the bridge API. For users who cannot immediately upgrade: Stop the bridge, or block loopback access to port 8080, when the bridge is not actively in use; avoid running the bridge alongside untrusted MCP servers, browser extensions, or other untrusted local processes; avoid browsing untrusted sites while the bridge is running (DNS rebinding mitigation); and/or run the bridge under a dedicated user account or in a sandbox/container with no access to sensitive files.","aliases":["GHSA-7jj9-4qqq-4xc4"],"modified":"2026-07-22T05:32:40.410911661Z","published":"2026-07-20T17:06:22.232Z","database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-22","CWE-306","CWE-346"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/46xxx/CVE-2026-46555.json"},"references":[{"type":"WEB","url":"https://github.com/verygoodplugins/whatsapp-mcp/blob/main/SECURITY.md"},{"type":"WEB","url":"https://github.com/verygoodplugins/whatsapp-mcp/releases/tag/v0.2.1"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/46xxx/CVE-2026-46555.json"},{"type":"ADVISORY","url":"https://github.com/verygoodplugins/whatsapp-mcp/security/advisories/GHSA-7jj9-4qqq-4xc4"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-46555"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/verygoodplugins/whatsapp-mcp","events":[{"introduced":"0"},{"fixed":"6bb5359e8ee68e3285745c8bb86d6c9be88ae2b1"}],"database_specific":{"source":["AFFECTED_FIELD","REFERENCES"],"extracted_events":[{"introduced":"0"},{"fixed":"0.2.1"}]}}],"versions":["v0.2.0","v0.1.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-46555.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N"}]}