A vulnerability exists in the writeCanvas function of bazylhorsey obsidian‑mcp‑server version 1.0.0, where unvalidated file paths are accepted. An attacker with local access to the server can craft a request that forces the function to write or overwrite files outside the intended canvas directory, enabling arbitrary file creation or modification. This flaw is a classic path traversal issue (CWE‑22). The impact is disclosure and potential modification of system files, which could lead to further compromise if critical files are affected. The CVSS score of 4.8 reflects a moderate severity for a local vulnerability, and the issue requires local interaction with the server. The project has acknowledged the bug but no remediation has been released yet.

The affected product is bazylhorsey obsidian‑mcp‑server, currently released at version 1.0.0. No other versions or variants are listed as impacted. Systems running this version and exposing the CanvasService API are susceptible.

The vulnerability can be exploited by any entity that can invoke the writeCanvas path on the server. Because the flaw is local, the attack requires physical or remote side‑channel access to the host, such as a compromised user session or insecure SSH access. There is no publicly available exploit, and the EPSS score is not reported, indicating limited known exploitation. The CVSS metric indicates a moderate risk, and the vulnerability is not present in the CISA KEV catalogue. If an attacker can reach the writeCanvas endpoint, they can deliver a crafted file path to create or overwrite arbitrary files within the server’s filesystem, potentially allowing privilege escalation or persistence. No remote network exposure or privilege escalation vectors are described in the available data.