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CVE-2026-54618 (GCVE-0-2026-54618)

Vulnerability from cvelistv5 – Published: 2026-09-17 19:45 – Updated: 2026-09-17 19:45
VLAI
Title
Obsidian Web MCP: Unauthenticated vault access: /oauth/authorize auto-approves without authenticating the user
Summary
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.
Severity
9.4 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L
CWE
  • CWE-306 - Missing Authentication for Critical Function
  • CWE-522 - Insufficiently Protected Credentials
  • CWE-601 - URL Redirection to Untrusted Site ('Open Redirect')
Assigner
References
Impacted products
Vendor Product Version CPE status
jimprosser obsidian-web-mcp Affected: < 0.2.0
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{
  "containers": {
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      "affected": [
        {
          "product": "obsidian-web-mcp",
          "vendor": "jimprosser",
          "versions": [
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              "version": "\u003c 0.2.0"
            }
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      "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."
        }
      ],
      "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"
          }
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      "problemTypes": [
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          "descriptions": [
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              "description": "CWE-306: Missing Authentication for Critical Function",
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        {
          "descriptions": [
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              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-601",
              "description": "CWE-601: URL Redirection to Untrusted Site (\u0027Open Redirect\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
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      "providerMetadata": {
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        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
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          "name": "https://github.com/jimprosser/obsidian-web-mcp/security/advisories/GHSA-hwhg-mrjc-8g43",
          "tags": [
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          ],
          "url": "https://github.com/jimprosser/obsidian-web-mcp/security/advisories/GHSA-hwhg-mrjc-8g43"
        },
        {
          "name": "https://github.com/jimprosser/obsidian-web-mcp/pull/30",
          "tags": [
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          "url": "https://github.com/jimprosser/obsidian-web-mcp/pull/30"
        },
        {
          "name": "https://github.com/jimprosser/obsidian-web-mcp/commit/e4924f096ee7494a7999d6c0cceca9be08e48eef",
          "tags": [
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        },
        {
          "name": "https://github.com/jimprosser/obsidian-web-mcp/releases/tag/v0.2.0",
          "tags": [
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          "url": "https://github.com/jimprosser/obsidian-web-mcp/releases/tag/v0.2.0"
        }
      ],
      "source": {
        "advisory": "GHSA-hwhg-mrjc-8g43",
        "discovery": "UNKNOWN"
      },
      "title": "Obsidian Web MCP: Unauthenticated vault access: /oauth/authorize auto-approves without authenticating the user"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-54618",
    "datePublished": "2026-09-17T19:45:15.384Z",
    "dateReserved": "2026-06-15T20:07:02.184Z",
    "dateUpdated": "2026-09-17T19:45:15.384Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
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      "date": "2026-09-18",
      "epss": "0.00399",
      "percentile": "0.33961"
    },
    "nvd": {
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                "product": "obsidian-web-mcp",
                "vendor": "jimprosser",
                "versions": [
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                    "status": "affected",
                    "version": "\u003c 0.2.0"
                  }
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        ],
        "cveTags": [],
        "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."
          }
        ],
        "id": "CVE-2026-54618",
        "lastModified": "2026-09-17T20:16:51.823",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "LOW",
                "baseScore": 9.4,
                "baseSeverity": "CRITICAL",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
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                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L",
                "version": "3.1"
              },
              "exploitabilityScore": 3.9,
              "impactScore": 5.5,
              "source": "security-advisories@github.com",
              "type": "Secondary"
            }
          ]
        },
        "published": "2026-09-17T20:16:51.823",
        "references": [
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            "url": "https://github.com/jimprosser/obsidian-web-mcp/commit/e4924f096ee7494a7999d6c0cceca9be08e48eef"
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            "url": "https://github.com/jimprosser/obsidian-web-mcp/releases/tag/v0.2.0"
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            "url": "https://github.com/jimprosser/obsidian-web-mcp/security/advisories/GHSA-hwhg-mrjc-8g43"
          }
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        "sourceIdentifier": "security-advisories@github.com",
        "vulnStatus": "Received",
        "weaknesses": [
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                "value": "CWE-306"
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                "value": "CWE-522"
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                "lang": "en",
                "value": "CWE-601"
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            "source": "security-advisories@github.com",
            "type": "Primary"
          }
        ]
      }
    }
  }
}



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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
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