obsidian-tc MCP server CVE-2026-77363 and CVE-2026-77366: HTTP transport without Origin / DNS-rebinding protection (drive-by full vault access on localhost with auth.mode none) and tokens that can reach any configured vault. How do I fix it?

What it is: obsidian-tc is an MCP (Model Context Protocol) server that lets AI agents read and write Obsidian vaults. On 2026-10-23 it published two critical advisories, both fixed in 1.3.1. CVE-2026-77363: its Streamable HTTP transport didn't validate the Origin or Host headers, and the documented loopback setup used auth.mode "none", so a web page you visit could use DNS rebinding or a forged origin to talk to the local server and get full read/write access to your vaults. CVE-2026-77366: tools didn't check the vault named in a request against the vault the caller's token was bound to, so any valid token could read, write or delete any configured vault, breaking multi-user isolation. Am I affected: - obsidian-tc below 1.3.1 (version 1.3.0 was never published to npm; 1.3.1 is the first fixed release). Check: npm ls -g obsidian-tc, or the version your MCP client config launches (for example an npx command line). - Drive-by risk: you run the HTTP transport on loopback with auth.mode "none". The stdio transport isn't the issue described. - Cross-vault risk: one server process serves several vaults or users with different tokens. Fix: 1. Upgrade to obsidian-tc 1.3.1 or later and restart the server (pin the version in your MCP client config rather than relying on a cached npx copy). 1.3.1 enables DNS-rebinding protection with allowed hosts and origins and rejects bad origins with HTTP 403. 2. Until upgraded: don't run the HTTP transport with auth.mode "none"; require JWT auth, or use stdio. Run one vault per server process (or a separate process and credential per tenant). 3. General MCP hygiene: any local MCP server on HTTP should require auth and validate Origin; local doesn't mean safe from websites in your browser. 4. If you ran an affected HTTP setup, check your vaults for unexpected edits or deletions (Obsidian's file recovery or git history help) and reissue tokens. Verify: the server reports 1.3.1+, a request with a foreign Origin header gets 403, and a token for one vault can't access another. Sources: https://github.com/The-40-Thieves/obsidian-tc/security/advisories/GHSA-pqh8-4pj7-32xx https://github.com/The-40-Thieves/obsidian-tc/security/advisories/GHSA-84c9-qqpq-2pq5 https://github.com/The-40-Thieves/obsidian-tc/releases/tag/v1.3.1 https://nvd.nist.gov/vuln/detail/CVE-2026-77363