{"id":"CVE-2026-55637","title":"genieacs-mcp is an MCP server for GenieACS written in Go","summary":"genieacs-mcp is an MCP server for GenieACS written in Go. Prior to 0.3.2, the Streamable HTTP transport in cmd/server/main.go creates an unauthenticated /mcp listener on the default MCP_LISTEN_ADDR value 127.0.0.1:8080 when MCP_AUTH_TOKE…","severity":"high","cwe":["CWE-346"],"vendor":"geiserx","product":"github.com/geiserx/genieacs-mcp","affected":["github.com/geiserx/genieacs-mcp <= 0.3.1"],"patched":["github.com/geiserx/genieacs-mcp 0.3.2"],"published":"2026-08-25","updated":"2026-09-09","sourceUpdated":"2026-09-09T21:07:31.353","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-55637","references":[{"url":"https://github.com/GeiserX/genieacs-mcp/commit/577306d78190622eee97e362b042a69499ef373f","label":"security-advisories@github.com"},{"url":"https://github.com/GeiserX/genieacs-mcp/pull/26","label":"security-advisories@github.com"},{"url":"https://github.com/GeiserX/genieacs-mcp/releases/tag/v0.3.2","label":"security-advisories@github.com"},{"url":"https://github.com/GeiserX/genieacs-mcp/security/advisories/GHSA-cmwv-wf9p-p8wx","label":"security-advisories@github.com"},{"url":"https://github.com/GeiserX/genieacs-mcp/security/advisories/GHSA-cmwv-wf9p-p8wx","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"},{"url":"https://github.com/advisories/GHSA-cmwv-wf9p-p8wx"}],"tags":["nvd","ghsa","go"],"epss":0.00205,"epssPercentile":0.10771,"aliases":["GHSA-cmwv-wf9p-p8wx"],"ecosystem":"go","ingestedAt":"2026-08-25T18:30:21.350Z","slug":"CVE-2026-55637","body":"## Overview\n\ngenieacs-mcp is an MCP server for GenieACS written in Go. Prior to 0.3.2, the Streamable HTTP transport in cmd/server/main.go creates an unauthenticated /mcp listener on the default MCP_LISTEN_ADDR value 127.0.0.1:8080 when MCP_AUTH_TOKEN is unset and the httpSrv.Start(addr) branch does not validate the Host or Origin headers. A malicious website can use DNS rebinding to send browser requests with attacker-controlled Host and Origin values to the loopback listener, initialize an MCP session, list tools, and invoke operations against the GenieACS NBI configured by ACS_URL. Successful exploitation can expose or modify CPE management state, including device reboots, firmware tasks, TR-069 parameter changes, presets, provisions, tags, connection requests, and task operations. The npm wrapper is not affected because it forces TRANSPORT=stdio and does not expose an HTTP listener. This issue is fixed in version 0.3.2.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Package advisory (CVE-2026-55637)\n\nAffected packages:\n\n- `github.com/geiserx/genieacs-mcp <= 0.3.1`\n\nPatched in:\n\n- `github.com/geiserx/genieacs-mcp 0.3.2`\n\nSource: https://github.com/advisories/GHSA-cmwv-wf9p-p8wx","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}