Obsidian Web MCP: Unauthenticated vault access: /oauth/authorize auto-approves without authenticating the user

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-54618
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-17 20:16:51 UTC
Updated2026-09-30 17:32:07 UTC
DescriptionObsidian 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.

Risk And Classification

Primary CVSS: v3.1 9.4 CRITICAL from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L

EPSS: 0.005070000 probability, percentile 0.414860000 (date 2026-10-11)

Problem Types: CWE-306 | CWE-522 | CWE-601 | CWE-306 CWE-306: Missing Authentication for Critical Function | CWE-522 CWE-522: Insufficiently Protected Credentials | CWE-601 CWE-601: URL Redirection to Untrusted Site ('Open Redirect')

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary9.4CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L
3.1CNADECLARED9.4CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
Low

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Jimprosser Obsidian-web-mcp affected < 0.2.0 Not specified

References

ReferenceSourceLinkTags
github.com/jimprosser/obsidian-web-mcp/security/advisories/GHSA-hwhg-mrj... 134c704f-9b21-4f2e-91b3-4a467353bcc0 github.com
github.com/jimprosser/obsidian-web-mcp/pull/30 [email protected] github.com
github.com/jimprosser/obsidian-web-mcp/commit/e4924f096ee7494a7999d6c0cc... [email protected] github.com
github.com/jimprosser/obsidian-web-mcp/releases/tag/v0.2.0 [email protected] github.com
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