Description
SiYuan before v3.7.4 contains a cross-site scripting vulnerability in the file upload validation flow that fails to escape filenames before inserting them into HTML via insertAdjacentHTML. Attackers can craft a malicious filename containing script payloads that execute with full OS command access when a user drags, drops, or pastes the file into the editor.
Published: 2026-08-18
Score: 9.3 Critical
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories

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History

Tue, 18 Aug 2026 11:30:00 +0000

Type Values Removed Values Added
Description SiYuan before v3.7.4 contains a cross-site scripting vulnerability in the file upload validation flow that fails to escape filenames before inserting them into HTML via insertAdjacentHTML. Attackers can craft a malicious filename containing script payloads that execute with full OS command access when a user drags, drops, or pastes the file into the editor.
Title SiYuan before v3.7.4 XSS-to-RCE via malicious filename upload
First Time appeared B3log
B3log siyuan
Weaknesses CWE-79
CPEs cpe:2.3:a:b3log:siyuan:*:*:*:*:*:*:*:*
Vendors & Products B3log
B3log siyuan
References
Metrics cvssV3_1

{'score': 8.6, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H'}

cvssV4_0

{'score': 9.3, 'vector': 'CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H'}

Subscriptions

B3log Siyuan
cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-08-18T11:19:34.741Z

Reserved: 2026-08-17T10:48:45.738Z

Link: CVE-2026-74902

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-18T12:19:30.370

Modified: 2026-08-18T12:19:30.370

Link: CVE-2026-74902

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-18T12:30:04Z

Weaknesses
  • CWE-79

    Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')