{"id":"CVE-2026-54618","state":"PUBLISHED","title":"Obsidian Web MCP: Unauthenticated vault access: /oauth/authorize auto-approves without authenticating the user","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.","publishedAt":"2026-09-17T19:45:15.384Z","updatedAt":"2026-09-24T20:40:37.956Z","severity":{"score":9.4,"label":"Critical","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L","source":"GitHub_M"},"assigner":"GitHub_M","products":["jimprosser obsidian-web-mcp"],"affected":[{"vendor":"jimprosser","product":"obsidian-web-mcp","versions":[{"version":"< 0.2.0","status":"affected"}]}],"references":["https://github.com/jimprosser/obsidian-web-mcp/security/advisories/GHSA-hwhg-mrjc-8g43","https://github.com/jimprosser/obsidian-web-mcp/pull/30","https://github.com/jimprosser/obsidian-web-mcp/commit/e4924f096ee7494a7999d6c0cceca9be08e48eef","https://github.com/jimprosser/obsidian-web-mcp/releases/tag/v0.2.0"],"weaknesses":["CWE-306","CWE-522","CWE-601"],"ingestedAt":"2026-10-29T20:12:24.861Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/54xxx/CVE-2026-54618.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-54618","state":"PUBLISHED","datePublished":"2026-09-17T19:45:15.384Z","dateUpdated":"2026-09-24T20:40:37.956Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-06-15T20:07:02.184Z"},"containers":{"cna":{"title":"Obsidian Web MCP: Unauthenticated vault access: /oauth/authorize auto-approves without authenticating the user","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"jimprosser","product":"obsidian-web-mcp","versions":[{"version":"< 0.2.0","status":"affected"}]}],"references":[{"url":"https://github.com/jimprosser/obsidian-web-mcp/security/advisories/GHSA-hwhg-mrjc-8g43","name":"https://github.com/jimprosser/obsidian-web-mcp/security/advisories/GHSA-hwhg-mrjc-8g43","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/jimprosser/obsidian-web-mcp/pull/30","name":"https://github.com/jimprosser/obsidian-web-mcp/pull/30","tags":["x_refsource_MISC"]},{"url":"https://github.com/jimprosser/obsidian-web-mcp/commit/e4924f096ee7494a7999d6c0cceca9be08e48eef","name":"https://github.com/jimprosser/obsidian-web-mcp/commit/e4924f096ee7494a7999d6c0cceca9be08e48eef","tags":["x_refsource_MISC"]},{"url":"https://github.com/jimprosser/obsidian-web-mcp/releases/tag/v0.2.0","name":"https://github.com/jimprosser/obsidian-web-mcp/releases/tag/v0.2.0","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"LOW","baseScore":9.4,"baseSeverity":"CRITICAL","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-306","lang":"en","description":"CWE-306: Missing Authentication for Critical Function","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-522","lang":"en","description":"CWE-522: Insufficiently Protected Credentials","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-601","lang":"en","description":"CWE-601: URL Redirection to Untrusted Site ('Open Redirect')","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-09-17T19:45:15.384Z"},"source":{"advisory":"GHSA-hwhg-mrjc-8g43","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/jimprosser/obsidian-web-mcp/security/advisories/GHSA-hwhg-mrjc-8g43","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-24T20:40:24.993933Z","id":"CVE-2026-54618","options":[{"Exploitation":"poc"},{"Automatable":"yes"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-24T20:40:37.956Z"}}]}}}