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.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
High
Complete data leak
Integrity
High
Complete data modification
Availability
Low
Partial disruption
CVSS Vector v3.1
Weakness Type (CWE)
References 4
https://github.com/jimprosser/obsidian-web-mcp/commit/e4924f096ee7494a7999d6c0c…
security-advisories@github.com
https://github.com/jimprosser/obsidian-web-mcp/pull/30
security-advisories@github.com
https://github.com/jimprosser/obsidian-web-mcp/releases/tag/v0.2.0
security-advisories@github.com
https://github.com/jimprosser/obsidian-web-mcp/security/advisories/GHSA-hwhg-mr…
security-advisories@github.com