6.9

CVE-2026-59809: siyuan-note siyuan

CVSS: 6.9v4.0MediumDeferred
Published 22-08-2026Last modified 26-08-2026
Open JSON

Vulnerability summary

CVE-2026-59809 is a medium (CVSS 6.9) vulnerability in siyuan-note siyuan. EPSS estimates a 0.41% chance of exploitation in the next 30 days, higher than 34.4% of scored vulnerabilities.

Overall risk
28/100
0100
Medium · default modelHow is this calculated?
CVSS score
6.9/10
010
Medium · v4.0 (CVE.org)
EPSS score
0.41%
0%100%
Low · +0.17 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 22-08-2026
    PublishedVulnerability first disclosed.
  2. 26-08-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

4 scores · 2 sources · 2 versions

EPSS trend

Probability

0.41%

Chance of exploitation in the next 30 days

Percentile

34%

Versus all other CVEs

30-day change

+0.17 pp

From 0.24% on 21-09-2026

21-09-202621-10-2026
EPSS score
0.41%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Siyuan-note1 product

1 vendor · 1 product

References

2 links