CVE-2026-59809
SiYuan before v3.8.0 Secret Exfiltration via http_request URL
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.
INFO
Published Date :
Aug. 22, 2026, 1:16 p.m.
Last Modified :
Oct. 12, 2026, 4:10 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 3.1 | MEDIUM | MITRE-CVE | ||||
| CVSS 4.0 | MEDIUM | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
- Update SiYuan to version 3.8.0 or later.
- Review and secure all http_request MCP tool configurations.
- Disable the http_request tool if not actively needed.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-59809.
| URL | Resource |
|---|---|
| https://github.com/siyuan-note/siyuan/security/advisories/GHSA-853m-gvvm-6rvx | |
| https://www.vulncheck.com/advisories/siyuan-before-secret-exfiltration-via-http-request-url |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-59809 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-59809
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-59809 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-59809 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Translated by [email protected]
Oct. 12, 2026
Action Type Old Value New Value Added Translation Title: siyuan de siyuan-note, Description: SiYuan anterior a la v3.8.0 interpola marcadores de posición de secretos en el parámetro URL de destino de la herramienta MCP http_request, lo que permite a los atacantes exfiltrar secretos almacenados. Un cliente MCP puede elaborar una solicitud con una URL controlada por el atacante que contenga marcadores de posición de secretos para enviar valores de secretos en texto plano a cualquier host público sin confirmación. -
CVE Modified by [email protected]
Aug. 26, 2026
Action Type Old Value New Value Added Reference https://github.com/siyuan-note/siyuan/security/advisories/GHSA-853m-gvvm-6rvx Added Reference https://www.vulncheck.com/advisories/siyuan-before-secret-exfiltration-via-http-request-url Removed Reference https://github.com/siyuan-note/siyuan/security/advisories/GHSA-853m-gvvm-6rvx Removed Reference https://www.vulncheck.com/advisories/siyuan-before-secret-exfiltration-via-http-request-url -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Aug. 26, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-59809', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-08-26T15:55:26.241710Z'} -
New CVE Received by [email protected]
Aug. 22, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'siyuan-note', 'product': 'siyuan', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '3.8.0', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '3.8.0', 'versionType': 'semver'}], 'packageURL': 'pkg:golang/github.com/siyuan-note/siyuan', 'defaultStatus': 'unaffected'}] 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. Added CVSS V4.0 AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CVSS V3.1 AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N Added CWE CWE-201 Added Reference https://github.com/siyuan-note/siyuan/security/advisories/GHSA-853m-gvvm-6rvx Added Reference https://www.vulncheck.com/advisories/siyuan-before-secret-exfiltration-via-http-request-url