CVE-2026-87811: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in siyuan-note siyuan
SiYuan before v3.8.2 inserts persisted notebook template paths into HTML input value attributes without proper attribute encoding. Attackers can craft malicious template paths that break out of the attribute context and execute JavaScript when a victim opens notebook configuration, enabling same-origin API requests and application state manipulation.
AI Analysis
Technical Summary
SiYuan versions prior to 3.8.2 improperly neutralize input during web page generation by inserting persisted notebook template paths into HTML input value attributes without proper attribute encoding. This vulnerability enables attackers to break out of the attribute context and execute arbitrary JavaScript code when a victim opens the notebook configuration interface. Exploitation could lead to same-origin API requests and manipulation of the application's state, posing a significant security risk.
Potential Impact
Successful exploitation allows an attacker to execute arbitrary JavaScript in the context of the affected application, potentially enabling unauthorized API requests and manipulation of application state. This could lead to data exposure or unauthorized actions within the application environment.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Users should upgrade to SiYuan version 3.8.2 or later once available. Until then, avoid opening untrusted notebook configurations that might contain malicious template paths.
CVE-2026-87811: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in siyuan-note siyuan
Description
SiYuan before v3.8.2 inserts persisted notebook template paths into HTML input value attributes without proper attribute encoding. Attackers can craft malicious template paths that break out of the attribute context and execute JavaScript when a victim opens notebook configuration, enabling same-origin API requests and application state manipulation.
CVSS v4.0
Score 8.4high
Affected software
pkg:github/siyuan-note/siyuanRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
SiYuan versions prior to 3.8.2 improperly neutralize input during web page generation by inserting persisted notebook template paths into HTML input value attributes without proper attribute encoding. This vulnerability enables attackers to break out of the attribute context and execute arbitrary JavaScript code when a victim opens the notebook configuration interface. Exploitation could lead to same-origin API requests and manipulation of the application's state, posing a significant security risk.
Potential Impact
Successful exploitation allows an attacker to execute arbitrary JavaScript in the context of the affected application, potentially enabling unauthorized API requests and manipulation of application state. This could lead to data exposure or unauthorized actions within the application environment.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Users should upgrade to SiYuan version 3.8.2 or later once available. Until then, avoid opening untrusted notebook configurations that might contain malicious template paths.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- VulnCheck
- Date Reserved
- 2026-09-09T10:30:15.669Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6aa14507acd9273b49403556
Added to database: 09/09/2026, 11:37:43 UTC
Last enriched: 09/09/2026, 11:52:45 UTC
Last updated: 09/09/2026, 18:43:42 UTC
Views: 7
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