CVE-2026-61546 AnkiMCP: DNS rebinding reaches unauthenticated local AnkiMCP HTTP tools
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2026-61546?
CVE-2026-61546 is a high-severity vulnerability in ankimcp anki-mcp-server-addon, published on 28 Oct 2026.
Official 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.
Which versions are affected by CVE-2026-61546?
How do I fix CVE-2026-61546?
No fix has been published for CVE-2026-61546 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-61546 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-61546 exists.
Sources
Also known as GHSA-j9xx-59ph-wmr6.