{"cve":"CVE-2026-55637","nvd":{"published":"2026-08-25T18:17:56.157","modified":"2026-09-09T21:07:31.353","status":"Deferred","description":"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_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.","cvss_v4":{"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N","score":8.8},"cvss_v3":null,"cwes":["CWE-346"],"references":["https://github.com/GeiserX/genieacs-mcp/commit/577306d78190622eee97e362b042a69499ef373f","https://github.com/GeiserX/genieacs-mcp/pull/26","https://github.com/GeiserX/genieacs-mcp/releases/tag/v0.3.2","https://github.com/GeiserX/genieacs-mcp/security/advisories/GHSA-cmwv-wf9p-p8wx","https://github.com/GeiserX/genieacs-mcp/security/advisories/GHSA-cmwv-wf9p-p8wx"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:50:17.453294893+00:00"},"epss":{"cve":"CVE-2026-55637","score":0.00264,"percentile":0.18415,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-cmwv-wf9p-p8wx","url":"https://osv.dev/vulnerability/GHSA-cmwv-wf9p-p8wx","summary":"genieacs-mcp: DNS rebinding reaches local GenieACS MCP Streamable HTTP transport","modified":"2026-08-26T15:26:21.228089925Z","packages":[{"ecosystem":"Go","name":"github.com/geiserx/genieacs-mcp","purl":"pkg:golang/github.com/geiserx/genieacs-mcp","ranges":["<0.3.2"],"fixed":["0.3.2"]}]},{"id":"GO-2026-6295","url":"https://osv.dev/vulnerability/GO-2026-6295","summary":"genieacs-mcp: DNS rebinding reaches local GenieACS MCP Streamable HTTP transport in github.com/geiserx/genieacs-mcp","modified":"2026-08-26T15:15:13.378236720Z","packages":[{"ecosystem":"Go","name":"github.com/geiserx/genieacs-mcp","purl":"pkg:golang/github.com/geiserx/genieacs-mcp","ranges":["<0.3.2"],"fixed":["0.3.2"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}