CVE-2026-74902: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in siyuan-note siyuan
SiYuan note-taking software versions before 3.7.4 contain a critical cross-site scripting (XSS) vulnerability in the file upload validation process. The vulnerability arises because filenames are not properly escaped before being inserted into HTML using insertAdjacentHTML. An attacker can craft malicious filenames with embedded script payloads that execute with full OS command access when a user interacts with the file in the editor via drag, drop, or paste actions.
AI Analysis
Technical Summary
CVE-2026-74902 is a critical cross-site scripting vulnerability affecting SiYuan note-taking software versions prior to 3.7.4. The flaw exists in the file upload validation flow where filenames are inserted into HTML without proper escaping via insertAdjacentHTML. This allows attackers to embed script payloads in filenames that execute with full OS command privileges when a user drags, drops, or pastes the file into the editor interface. The vulnerability has a CVSS 4.0 score of 9.3, indicating high exploitability and impact.
Potential Impact
Successful exploitation allows remote attackers to execute arbitrary scripts with full OS command access on the victim's machine when interacting with maliciously named files in the editor. This can lead to full system compromise or unauthorized actions performed with the user's privileges.
Mitigation Recommendations
Upgrade SiYuan to version 3.7.4 or later where this vulnerability has been fixed. Users should avoid opening or interacting with files from untrusted sources until patched.
CVE-2026-74902: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in siyuan-note siyuan
Description
SiYuan note-taking software versions before 3.7.4 contain a critical cross-site scripting (XSS) vulnerability in the file upload validation process. The vulnerability arises because filenames are not properly escaped before being inserted into HTML using insertAdjacentHTML. An attacker can craft malicious filenames with embedded script payloads that execute with full OS command access when a user interacts with the file in the editor via drag, drop, or paste actions.
CVSS v4.0
Score 9.3critical
Affected software
siyuan-note
siyuan
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-74902 is a critical cross-site scripting vulnerability affecting SiYuan note-taking software versions prior to 3.7.4. The flaw exists in the file upload validation flow where filenames are inserted into HTML without proper escaping via insertAdjacentHTML. This allows attackers to embed script payloads in filenames that execute with full OS command privileges when a user drags, drops, or pastes the file into the editor interface. The vulnerability has a CVSS 4.0 score of 9.3, indicating high exploitability and impact.
Potential Impact
Successful exploitation allows remote attackers to execute arbitrary scripts with full OS command access on the victim's machine when interacting with maliciously named files in the editor. This can lead to full system compromise or unauthorized actions performed with the user's privileges.
Mitigation Recommendations
Upgrade SiYuan to version 3.7.4 or later where this vulnerability has been fixed. Users should avoid opening or interacting with files from untrusted sources until patched.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- VulnCheck
- Date Reserved
- 2026-08-17T10:48:45.738Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6a844363c6e8be033222949e
Added to database: 08/18/2026, 11:34:59 UTC
Last enriched: 09/11/2026, 23:18:46 UTC
Last updated: 10/02/2026, 14:46:10 UTC
Views: 53
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