Description
Obsidian Web MCP is a secure remote MCP server for Obsidian vaults. Prior to 0.2.0, /oauth/authorize issues an authorization code without a login, consent, or session check, and /oauth/token can exchange that code for the static VAULT_MCP_TOKEN without authenticating a client. An unauthenticated remote caller who can reach the intended tunnel deployment can therefore call /mcp and use vault_read, vault_write, vault_search, vault_list, vault_move, and vault_delete against the entire vault. Optional PKCE does not prevent an attacker-initiated flow, and unauthenticated /oauth/register also exposes a client_credentials path by returning the configured VAULT_OAUTH_CLIENT_SECRET. This issue is fixed in version 0.2.0.
References5
- github.com/jimprosser/obsidian-web-mcp/commit/e4924f096ee7494a7…
- github.com/jimprosser/obsidian-web-mcp/pull/30
- github.com/jimprosser/obsidian-web-mcp/releases/tag/v0.2.0
- github.com/jimprosser/obsidian-web-mcp/security/advisories/GHSA…
- github.com/jimprosser/obsidian-web-mcp/security/advisories/GHSA…
Metrics
- CVSS 3.1
-
9.4
CRITICAL
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L - EPSS — exploit probability
- 1% percentile: 44 · as of 8 November 2026
- CWE
- CWE-306CWE-522CWE-601
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.