Obsidian Web MCP: Unauthenticated vault access: /oauth/authorize auto-approves without authenticating the user (CVE-2026-54618) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-54618

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

Answer in brief

CVE-2026-54618 records a Unknown severity vulnerability in Obsidian Web MCP: Unauthenticated vault access: /oauth/authorize auto-approves without authenticating the user. The current sources do not mark it as known exploited. The current feed maps jimprosser/obsidian-web-mcp (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 17, 2026Updated Sep 17, 2026Source checked Sep 17, 2026First seen by HOL Sep 17, 2026Material review Sep 17, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Not reported

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps jimprosser/obsidian-web-mcp (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
jimprosser/obsidian-web-mcpgeneric	< 0.2.0	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for jimprosser/obsidian-web-mcp.
Review the reported fix. Monitor this advisory for an available fix and review any installs of the affected package.

Evidence timeline and material changes

Published upstream
Sep 17, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 17, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 17, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.