CVE-2026-59809

MEDIUM 4.9

SiYuan before v3.8.0 Secret Exfiltration via http_request URL

CVSS Score

4.9

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-201
Vendor	siyuan-note
Product	siyuan
Published	Aug 22, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

High

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

None

Affected Versions

siyuan-note / siyuan

0 < 3.8.0

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/siyuan-note/siyuan/security/advisories/GHSA-853m-gvvm-6rvx vulncheck.com: https://www.vulncheck.com/advisories/siyuan-before-secret-exfiltration-via-http-request-url

Credits

🔍 alham-rizvi