CVE-2026-59809
SiYuan before v3.8.0 Secret Exfiltration via http_request URL
- State
- Published
- Severity
- 6.9 Medium
- Published
- Aug 22, 2026
- Updated
- Aug 26, 2026
- Reserved
- Jul 7, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 6.9 Medium | CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N | VulnCheck |
| 3.1 | 4.9 Medium | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N | VulnCheck |
Weaknesses
- CWE-201 Insertion of Sensitive Information Into Sent Data
Affected Products
| Product | Versions |
|---|---|
siyuansiyuan-note |
|
References
- GitHub Security Advisory (GHSA-853m-gvvm-6rvx)vendor-advisory
- VulnCheck Advisory: SiYuan before v3.8.0 Secret Exfiltration via http_request URLthird-party-advisory
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