CVE-2026-54618: CWE-306: Missing Authentication for Critical Function in jimprosser obsidian-web-mcp
CVE-2026-54618 is a critical vulnerability in jimprosser's obsidian-web-mcp prior to version 0.2.0. The issue involves missing authentication on critical OAuth endpoints, allowing unauthenticated remote attackers to obtain authorization codes and exchange them for static tokens without login or consent. This enables unauthorized access to sensitive vault operations such as reading, writing, searching, listing, moving, and deleting vault contents. The vulnerability also exposes client credentials via an unauthenticated registration endpoint. The flaw is fixed in version 0.2.0.
AI Analysis
Technical Summary
Obsidian Web MCP versions before 0.2.0 have a missing authentication vulnerability (CWE-306) in their OAuth implementation. The /oauth/authorize endpoint issues authorization codes without verifying login, consent, or session, and the /oauth/token endpoint exchanges these codes for a static VAULT_MCP_TOKEN without client authentication. This allows unauthenticated remote attackers who can access the tunnel deployment to perform critical vault operations (/mcp endpoints) including vault_read, vault_write, vault_search, vault_list, vault_move, and vault_delete. Additionally, the /oauth/register endpoint exposes the VAULT_OAUTH_CLIENT_SECRET via a client_credentials path without authentication. Optional PKCE does not mitigate the attack. The vulnerability is resolved in obsidian-web-mcp version 0.2.0.
Potential Impact
An unauthenticated remote attacker can gain full unauthorized access to the vault by exploiting the OAuth endpoints, allowing them to read, modify, search, list, move, and delete vault data. The exposure of the client secret further compromises the security of the OAuth client credentials. This results in a critical confidentiality and integrity breach with limited availability impact.
Mitigation Recommendations
Upgrade obsidian-web-mcp to version 0.2.0 or later, where this vulnerability is fixed. Prior versions lack proper authentication on OAuth endpoints and should not be used in production environments. No other mitigations are indicated.
CVE-2026-54618: CWE-306: Missing Authentication for Critical Function in jimprosser obsidian-web-mcp
Description
CVE-2026-54618 is a critical vulnerability in jimprosser's obsidian-web-mcp prior to version 0.2.0. The issue involves missing authentication on critical OAuth endpoints, allowing unauthenticated remote attackers to obtain authorization codes and exchange them for static tokens without login or consent. This enables unauthorized access to sensitive vault operations such as reading, writing, searching, listing, moving, and deleting vault contents. The vulnerability also exposes client credentials via an unauthenticated registration endpoint. The flaw is fixed in version 0.2.0.
CVSS v3.1
Score 9.4critical
Affected software
jimprosser
obsidian-web-mcp
pkg:github/jimprosser/obsidian-web-mcpRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
Obsidian Web MCP versions before 0.2.0 have a missing authentication vulnerability (CWE-306) in their OAuth implementation. The /oauth/authorize endpoint issues authorization codes without verifying login, consent, or session, and the /oauth/token endpoint exchanges these codes for a static VAULT_MCP_TOKEN without client authentication. This allows unauthenticated remote attackers who can access the tunnel deployment to perform critical vault operations (/mcp endpoints) including vault_read, vault_write, vault_search, vault_list, vault_move, and vault_delete. Additionally, the /oauth/register endpoint exposes the VAULT_OAUTH_CLIENT_SECRET via a client_credentials path without authentication. Optional PKCE does not mitigate the attack. The vulnerability is resolved in obsidian-web-mcp version 0.2.0.
Potential Impact
An unauthenticated remote attacker can gain full unauthorized access to the vault by exploiting the OAuth endpoints, allowing them to read, modify, search, list, move, and delete vault data. The exposure of the client secret further compromises the security of the OAuth client credentials. This results in a critical confidentiality and integrity breach with limited availability impact.
Mitigation Recommendations
Upgrade obsidian-web-mcp to version 0.2.0 or later, where this vulnerability is fixed. Prior versions lack proper authentication on OAuth endpoints and should not be used in production environments. No other mitigations are indicated.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-06-15T20:07:02.184Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6aac478455bf5e2cf5d35f41
Added to database: 09/17/2026, 20:03:16 UTC
Last enriched: 09/17/2026, 20:16:40 UTC
Last updated: 09/17/2026, 20:21:28 UTC
Views: 4
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