9.3

CVE-2026-74902: siyuan-note siyuan Cross-site Scripting

CVSS: 9.3v4.0CriticalDeferred
Published 18-08-2026Last modified 08-10-2026
Open JSON

Vulnerability summary

CVE-2026-74902 is a critical (CVSS 9.3) Cross-site Scripting vulnerability in siyuan-note siyuan. EPSS estimates a 0.20% chance of exploitation in the next 30 days, higher than 9% of scored vulnerabilities.

Overall risk
70/100
0100
High · default modelHow is this calculated?
CVSS score
9.3/10
010
Critical · v4.0 (CVE.org)
EPSS score
0.20%
0%100%
Low · +0.05 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 18-08-2026
    PublishedVulnerability first disclosed.
  2. 08-10-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

4 scores · 2 sources · 2 versions

EPSS trend

Probability

0.20%

Chance of exploitation in the next 30 days

Percentile

9%

Versus all other CVEs

30-day change

+0.05 pp

From 0.15% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.20%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Siyuan-note1 product

1 vendor · 1 product

References

2 links