# CVE-2026-61546: AnkiMCP: DNS rebinding reaches unauthenticated local AnkiMCP HTTP tools


- **Severity:** High 8.8 (`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`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 28 Oct 2026
- **Updated:** 29 Oct 2026
- **Also known as:** GHSA-j9xx-59ph-wmr6

## 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.

Weakness: CWE-350 (Reliance on Reverse DNS Resolution for a Security-Critical Action), CWE-346 (Origin Validation Error)

## 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.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-61546 and fix it if it is affected.

What it is: CVE-2026-61546 is a high-severity vulnerability in ankimcp anki-mcp-server-addon, published on 28 Oct 2026. 
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-61546 exists.

Affected product: ankimcp anki-mcp-server-addon. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-61546/ (Markdown: https://insights.sbomify.com/CVE-2026-61546/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-61546
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-61546
- OSV: https://osv.dev/vulnerability/CVE-2026-61546

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-61546/
Summaries are generated and may contain mistakes; the official description above is the record.