Remote Secret Exfiltration Vulnerability in SiYuan by SiYuan Team
CVE-2026-59809

6.9MEDIUM

Key Information:

Vendor

Siyuan-note

Status
Siyuan
Vendor
CVE Published:
22 August 2026

What is CVE-2026-59809?

The vulnerability in SiYuan before version 3.8.0 allows attackers to exfiltrate sensitive stored secrets via manipulated destination URL parameters in the http_request MCP tool. By crafting requests with an attacker-controlled URL that contains secret placeholders, an MCP client can inadvertently transmit plaintext secret values to any public host without any confirmation, posing a significant risk to data confidentiality and integrity.

Affected Version(s)

siyuan 0 < 3.8.0

siyuan 3.8.0

References

https://github.com/siyuan-note/siyuan/security/advisories...
vendor-advisory
https://www.vulncheck.com/advisories/siyuan-before-secret...
third-party-advisory

CVSS V4

Score:
6.9
Severity:
MEDIUM
Confidentiality:
High
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

alham-rizvi
.