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.

Attack Vector Network

Attack Complexity Low

Privileges Required High

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact High

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required High

Scope Unchanged

Confidentiality Impact High

Integrity Impact None

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
siyuan-note siyuan unaffected
Version Status Constraints
0 affected < 3.8.0
3.8.0 unaffected —

No data.

No data.

OpenCVE Enrichment is a feature of OpenCVE that uses AI to automatically link vendors and products to CVEs. Learn more on GitHub.

No data.

Project Subscriptions

Vendors Products
B3log Subscribe
Siyuan Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

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

Sat, 22 Aug 2026 12:45:00 +0000

Type Values Removed Values Added
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.
Title SiYuan before v3.8.0 Secret Exfiltration via http_request URL
First Time appeared B3log
B3log siyuan
Weaknesses CWE-201
CPEs cpe:2.3:a:b3log:siyuan:*:*:*:*:*:*:*:*
Vendors & Products B3log
B3log siyuan
References
Metrics cvssV3_1

{'score': 4.9, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N'}

cvssV4_0

{'score': 6.9, 'vector': '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'}

Projects

Sign in to view the affected projects.

cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-08-22T12:26:35.098Z

Reserved: 2026-07-07T14:39:14.063Z

Link: CVE-2026-59809

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-22T13:16:39.127

Modified: 2026-08-22T13:16:39.127

Link: CVE-2026-59809

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-22T13:30:17Z

Weaknesses