CVE-2026-66012
Public exploit code is available. Proof-of-concept or working exploit code for CVE-2026-66012 is indexed in GitHub PoC. Expect opportunistic scanning and exploitation attempts — prioritize remediation even though it is not (yet) in the CISA KEV catalog.
SiYuan before v3.7.2 contains a missing authorization vulnerability in the POST /mcp kernel endpoint, which is gated only by a general auth check (model.CheckAuth) with no admin-role or read-only enforcement. This exposes 31 MCP tools, including a file tool with list/read/write/delete/rename/copy actions across the entire workspace. When the Publish server is enabled in anonymous mode (Conf.Publish.Enable=true and Conf.Publish.Auth.Enable=false), the Publish reverse proxy attaches an anonymous RoleReader JWT to proxied requests, allowing a remote unauthenticated attacker to reach /mcp. The attacker can read conf/conf.json to extract accessAuthCode, api.token, and cookieKey in plaintext, write arbitrary files in the workspace, and plant a plugin into data/plugins/ that executes with nodeIntegration:true and no contextIsolation on the next desktop launch, leading to administrator takeover.
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Exploitation outlook
- Low exploitation risk0.44% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 37% of all EPSS-scored CVEs.
Exploit availability
Public exploit or proof-of-concept code for CVE-2026-66012 is indexed in these free datasets. Available exploit code raises real-world risk independent of the CVSS score.
- GitHub PoCPublic proof-of-concept repositories on GitHub reference this CVE.look it up ↗
Advisory coverage (1)
External references
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[](https://www.csirts.com/cve/CVE-2026-66012)