SiYuan is an open-source personal knowledge management system
Description
SiYuan is an open-source personal knowledge management system
AI Analyst Comment
Remediation
Apply vendor security updates immediately. Monitor for exploitation attempts and review access logs.
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VENDOR: SiYuan
PRODUCT: SiYuan
AFFECTED_VERSIONS: < 3.7.1
CONFIDENCE: high
MISSING: none
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Description Summary:
SiYuan is vulnerable to stored Cross-Site Scripting (XSS) due to improper neutralization of script-related HTML tags, potentially allowing remote execution of malicious scripts.
Executive Summary:
An unauthenticated Cross-Site Scripting (XSS) vulnerability in SiYuan could allow attackers to execute arbitrary code in the context of a user's session.
Vulnerability Details
CVE-ID: CVE-2026-59855
Affected Software: SiYuan
Affected Versions: < 3.7.1
Vulnerability: This is a stored Cross-Site Scripting (XSS) vulnerability (CWE-80) resulting from the failure to properly sanitize HTML input. As the attack vector is network-based and requires no authentication, an attacker can inject malicious scripts into the application that execute when viewed by other users.
Business Impact
Successful exploitation of this vulnerability can lead to full account takeover, session hijacking, and the theft of sensitive personal knowledge data stored within the SiYuan instance. With a CVSS score of 8.6, this flaw presents a high risk of unauthorized access and potential data exfiltration, significantly impacting the confidentiality and integrity of the user's workspace.
Remediation Plan
Immediate Action: Upgrade to SiYuan version 3.7.1 or later immediately to incorporate the necessary input sanitization patches.
Proactive Monitoring: Review web access logs for unusual patterns or payloads containing script tags associated with user input fields.
Compensating Controls: Implement a strict Content Security Policy (CSP) to restrict the sources from which scripts can be loaded, which may mitigate the impact of XSS attacks.
Exploitation Status
Public Exploit Available: false
Analyst Notes: As of July 10, 2026, there is no public information indicating active exploitation of this vulnerability. However, due to the nature of the flaw, the potential for exploitation is high.
Analyst Recommendation
Given the high CVSS severity and the ease of exploitation, organizations and individuals using SiYuan must prioritize updating to version 3.7.1. Failure to patch may allow attackers to compromise the integrity of the knowledge management system and gain unauthorized access to stored data.