CVE-2026-74902
SiYuan before v3.7.4 XSS-to-RCE via malicious filename upload
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.
INFO
Published Date :
Aug. 18, 2026, 12:19 p.m.
Last Modified :
Oct. 22, 2026, 10:10 p.m.
Remotely Exploit :
No
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 3.1 | HIGH | MITRE-CVE | ||||
| CVSS 4.0 | CRITICAL | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 4.0 | CRITICAL | [email protected] |
Solution
- Update SiYuan to version 3.7.4 or later.
- Avoid handling untrusted file uploads.
- Sanitize filenames before displaying them.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-74902.
| URL | Resource |
|---|---|
| https://github.com/siyuan-note/siyuan/security/advisories/GHSA-jf56-jrhq-j2qp | |
| https://www.vulncheck.com/advisories/siyuan-before-xss-to-rce-via-malicious-filename-upload |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-74902 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-74902
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-74902 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-74902 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Translated by [email protected]
Oct. 22, 2026
Action Type Old Value New Value Added Translation Title: siyuan de siyuan-note, Description: SiYuan antes de la v3.7.4 contiene una vulnerabilidad de cross-site scripting en el flujo de validación de carga de archivos que no logra escapar los nombres de archivo antes de insertarlos en HTML a través de insertAdjacentHTML. Los atacantes pueden crear un nombre de archivo malicioso que contiene cargas útiles de script que se ejecutan con acceso completo a comandos del sistema operativo cuando un usuario arrastra, suelta o pega el archivo en el editor. -
CVE Modified by [email protected]
Oct. 08, 2026
Action Type Old Value New Value Added Affected Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/74xxx/CVE-2026-74902.json">CVE-2026-74902</a> Added Reference https://github.com/siyuan-note/siyuan/security/advisories/GHSA-jf56-jrhq-j2qp Added Reference https://www.vulncheck.com/advisories/siyuan-before-xss-to-rce-via-malicious-filename-upload Removed Reference https://github.com/siyuan-note/siyuan/security/advisories/GHSA-jf56-jrhq-j2qp Removed Reference https://www.vulncheck.com/advisories/siyuan-before-xss-to-rce-via-malicious-filename-upload -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Aug. 18, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-74902', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-08-18T12:52:00.846926Z'} -
New CVE Received by [email protected]
Aug. 18, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'siyuan-note', 'product': 'siyuan', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '3.7.4', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '3.7.4', 'versionType': 'semver'}], 'packageURL': 'pkg:golang/siyuan', 'defaultStatus': 'unaffected'}] 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. Added CVSS V4.0 AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CVSS V3.1 AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H Added CWE CWE-79 Added Reference https://github.com/siyuan-note/siyuan/security/advisories/GHSA-jf56-jrhq-j2qp Added Reference https://www.vulncheck.com/advisories/siyuan-before-xss-to-rce-via-malicious-filename-upload