CVE-2026-54618 — Obsidian Web MCP is a secure remote MCP server for Obsidian vaults.¶
Key facts
CVE-2026-54618 is a Critical (9.4) vulnerability: Obsidian Web MCP is a secure remote MCP server for Obsidian vaults.. This entry ships a detection-only PoC and a Docker test lab.
| CVE | CVE-2026-54618 |
| Severity | Critical (9.4) |
| Detection / prevention | — |
| PoC | poc.py |
| Source | 2026/CVE-2026-54618/ |
Details¶
English | 한국어
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.
Vulnerability Details¶
| Property | Value |
|---|---|
| CVE ID | CVE-2026-54618 |
| CVSS Score | 9.4 |
Proof of Concept¶
Download¶
# Download PoC script
curl -O https://raw.githubusercontent.com/fankh/vulnerability-poc/main/2026/CVE-2026-54618/poc.py
Usage¶
# Run PoC against target
python3 poc.py --target <TARGET_URL>
# With authentication
python3 poc.py --target <TARGET_URL> --username <USER> --password <PASS>
⚠️ Warning: This PoC is for authorized security testing only. It uses detection-only techniques and does not exploit or damage target systems.
Test Lab¶
This repository includes a Docker-based test environment with both vulnerable and patched applications.
Quick Start¶
# Clone and navigate to CVE directory
cd CVE-2026-54618
# Start both applications
docker-compose up -d
# Run tests
./run-tests.sh # Linux/Mac
./run-tests.ps1 # Windows PowerShell
Application Endpoints¶
| Application | URL | Status |
|---|---|---|
| Vulnerable App | http://localhost:8080 | Shows vulnerability |
| Patched App | http://localhost:8081 | Demonstrates fix |
Directory Structure¶
├── README.md # English documentation
├── README_KO.md # Korean documentation
├── poc.py # PoC detection script
├── docker-compose.yml # Container orchestration
├── run-tests.sh # Linux/Mac test runner
├── run-tests.ps1 # Windows test runner
├── vulnerable-app/ # Vulnerable version
│ ├── app.py
│ ├── Dockerfile
│ └── requirements.txt
└── patched-app/ # Fixed version
├── app.py
├── Dockerfile
└── requirements.txt
References¶
- https://github.com/jimprosser/obsidian-web-mcp/commit/e4924f096ee7494a7999d6c0cceca9be08e48eef
- https://github.com/jimprosser/obsidian-web-mcp/pull/30
- https://github.com/jimprosser/obsidian-web-mcp/releases/tag/v0.2.0
- https://github.com/jimprosser/obsidian-web-mcp/security/advisories/GHSA-hwhg-mrjc-8g43
Generated by PoC Generator on 2026-09-18T06:36:24.799449065
Frequently asked questions¶
What is CVE-2026-54618?¶
CVE-2026-54618 is a Critical (9.4) vulnerability: Obsidian Web MCP is a secure remote MCP server for Obsidian vaults.. This entry ships a detection-only PoC and a Docker test lab.
How do I detect CVE-2026-54618?¶
Run the detection-only PoC included with this entry against your Docker test lab to confirm whether a target is affected; pair it with your own IDS logging.
How do I block or mitigate CVE-2026-54618?¶
Upgrade to a fixed version per the vendor advisory; the NVD record lists the affected versions. Use the included PoC to verify your remediation.
For authorized security testing and research only. See the full source and NVD record.