CVE-2026-59809
MEDIUM
NVD
CVSS Score
4.9
Severity
MEDIUM
Published
Aug 22, 2026
Vendor
unknown
Description
SiYuan before v3.8.0 interpolates secret placeholders into the destination URL parameter of the http_request MCP tool, allowing attackers to exfiltrate stored secrets. An MCP client can craft a request with an attacker-controlled URL containing secret placeholders to send plaintext secret values to any public host without confirmation.