{"id":"CVE-2026-61546","state":"PUBLISHED","title":"AnkiMCP: DNS rebinding reaches unauthenticated local AnkiMCP HTTP tools","description":"AnkiMCP is an Anki addon that implements an MCP server, enabling AI assistants to interact with the Anki flashcard application. Prior to version 0.21.0, `anki_mcp_server/mcp_server.py` globally disables FastMCP DNS-rebinding protection through `TransportSecuritySettings` with `enable_dns_rebinding_protection=False`, including for the default local Streamable HTTP listener. The defaults in `anki_mcp_server/config.py` enable `http_enabled` on `127.0.0.1:3141`, with an empty `http_path` selecting the root endpoint. No bearer token, API key, session secret, strict `Host` allowlist or strict `Origin` allowlist is enforced before `initialize`, `tools/list` and `tools/call` reach MCP dispatch. A victim who visits a malicious web page while Anki and the listener are running can have browser requests rebound to loopback, allowing the attacker to `initialize` MCP, enumerate tools, read the local collection, and perform enabled non-destructive note/deck creation or updates. The attacker needs neither LAN position nor a local process. Available operations depend on enabled tool filters; destructive tools are hidden unless `enabled_destructive_tools` is opted into, limiting deletion-level impact but not the exposed read/write operations. The reported harness confirms real MCP tool dispatch with substituted Anki bridge responses rather than demonstrating destructive changes to a real collection. Disabling protection for tunnels/proxies also disables it for the normal loopback configuration. This issue is fixed in version 0.21.0.","publishedAt":"2026-10-28T21:40:16.081Z","updatedAt":"2026-10-29T18:24:59.680Z","severity":{"score":8.8,"label":"High","version":"4.0","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","source":"GitHub_M"},"assigner":"GitHub_M","products":["ankimcp anki-mcp-server-addon"],"affected":[{"vendor":"ankimcp","product":"anki-mcp-server-addon","versions":[{"version":"< 0.21.0","status":"affected"}]}],"references":["https://github.com/ankimcp/anki-mcp-server-addon/security/advisories/GHSA-j9xx-59ph-wmr6","https://github.com/ankimcp/anki-mcp-server-addon/commit/6dcb6939b0ecc0801f45cf0d241dc946aad1654f","https://github.com/ankimcp/anki-mcp-server-addon/commit/d5306ff42d68f1e3b82a96878eb059437e820316","https://github.com/ankimcp/anki-mcp-server-addon/tree/v0.21.0"],"weaknesses":["CWE-346","CWE-350"],"ingestedAt":"2026-10-29T20:12:32.778Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/61xxx/CVE-2026-61546.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-61546","state":"PUBLISHED","datePublished":"2026-10-28T21:40:16.081Z","dateUpdated":"2026-10-29T18:24:59.680Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-07-10T16:27:03.094Z"},"containers":{"cna":{"title":"AnkiMCP: DNS rebinding reaches unauthenticated local AnkiMCP HTTP tools","descriptions":[{"lang":"en","value":"AnkiMCP is an Anki addon that implements an MCP server, enabling AI assistants to interact with the Anki flashcard application. Prior to version 0.21.0, `anki_mcp_server/mcp_server.py` globally disables FastMCP DNS-rebinding protection through `TransportSecuritySettings` with `enable_dns_rebinding_protection=False`, including for the default local Streamable HTTP listener. The defaults in `anki_mcp_server/config.py` enable `http_enabled` on `127.0.0.1:3141`, with an empty `http_path` selecting the root endpoint. No bearer token, API key, session secret, strict `Host` allowlist or strict `Origin` allowlist is enforced before `initialize`, `tools/list` and `tools/call` reach MCP dispatch. A victim who visits a malicious web page while Anki and the listener are running can have browser requests rebound to loopback, allowing the attacker to `initialize` MCP, enumerate tools, read the local collection, and perform enabled non-destructive note/deck creation or updates. The attacker needs neither LAN position nor a local process. Available operations depend on enabled tool filters; destructive tools are hidden unless `enabled_destructive_tools` is opted into, limiting deletion-level impact but not the exposed read/write operations. The reported harness confirms real MCP tool dispatch with substituted Anki bridge responses rather than demonstrating destructive changes to a real collection. Disabling protection for tunnels/proxies also disables it for the normal loopback configuration. This issue is fixed in version 0.21.0."}],"affected":[{"vendor":"ankimcp","product":"anki-mcp-server-addon","versions":[{"version":"< 0.21.0","status":"affected"}]}],"references":[{"url":"https://github.com/ankimcp/anki-mcp-server-addon/security/advisories/GHSA-j9xx-59ph-wmr6","name":"https://github.com/ankimcp/anki-mcp-server-addon/security/advisories/GHSA-j9xx-59ph-wmr6","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/ankimcp/anki-mcp-server-addon/commit/6dcb6939b0ecc0801f45cf0d241dc946aad1654f","name":"https://github.com/ankimcp/anki-mcp-server-addon/commit/6dcb6939b0ecc0801f45cf0d241dc946aad1654f","tags":["x_refsource_MISC"]},{"url":"https://github.com/ankimcp/anki-mcp-server-addon/commit/d5306ff42d68f1e3b82a96878eb059437e820316","name":"https://github.com/ankimcp/anki-mcp-server-addon/commit/d5306ff42d68f1e3b82a96878eb059437e820316","tags":["x_refsource_MISC"]},{"url":"https://github.com/ankimcp/anki-mcp-server-addon/tree/v0.21.0","name":"https://github.com/ankimcp/anki-mcp-server-addon/tree/v0.21.0","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"PASSIVE","vulnConfidentialityImpact":"HIGH","vulnIntegrityImpact":"HIGH","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"HIGH","subIntegrityImpact":"HIGH","subAvailabilityImpact":"NONE","baseScore":8.8,"baseSeverity":"HIGH","vectorString":"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","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-346","lang":"en","description":"CWE-346: Origin Validation Error","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-350","lang":"en","description":"CWE-350: Reliance on Reverse DNS Resolution for a Security-Critical Action","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-10-28T21:40:16.081Z"},"source":{"advisory":"GHSA-j9xx-59ph-wmr6","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/ankimcp/anki-mcp-server-addon/security/advisories/GHSA-j9xx-59ph-wmr6","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-10-29T18:24:19.481141Z","id":"CVE-2026-61546","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-29T18:24:59.680Z"}}]}}}