{"id":"CVE-2026-54618","summary":"Obsidian Web MCP: Unauthenticated vault access: /oauth/authorize auto-approves without authenticating the user","details":"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.","aliases":["GHSA-hwhg-mrjc-8g43"],"modified":"2026-09-19T03:46:30.288974027Z","published":"2026-09-17T19:45:15.384Z","database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-306","CWE-522","CWE-601"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/54xxx/CVE-2026-54618.json"},"references":[{"type":"WEB","url":"https://github.com/jimprosser/obsidian-web-mcp/releases/tag/v0.2.0"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/54xxx/CVE-2026-54618.json"},{"type":"ADVISORY","url":"https://github.com/jimprosser/obsidian-web-mcp/security/advisories/GHSA-hwhg-mrjc-8g43"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-54618"},{"type":"FIX","url":"https://github.com/jimprosser/obsidian-web-mcp/commit/e4924f096ee7494a7999d6c0cceca9be08e48eef"},{"type":"FIX","url":"https://github.com/jimprosser/obsidian-web-mcp/pull/30"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/jimprosser/obsidian-web-mcp","events":[{"introduced":"0"},{"fixed":"e4924f096ee7494a7999d6c0cceca9be08e48eef"}],"database_specific":{"source":["AFFECTED_FIELD","REFERENCES"],"extracted_events":[{"introduced":"0"},{"fixed":"0.2.0"}]}}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-54618.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L"}]}