9.3

CVE-2026-66396: SiYuan before v3.7.2 Stored XSS to RCE via title-img IAL

Deferred
Published 27-07-2026Last modified 17-09-2026

Vulnerability summary

CVE-2026-66396 is a critical (CVSS 9.3) Cross-site Scripting vulnerability in siyuan-note siyuan. EPSS estimates a 0.54% chance of exploitation in the next 30 days, higher than 44.6% 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
0.54%
0%100%
Low · +0.17 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Timeline

  1. 27-07-2026
    PublishedVulnerability first disclosed.
  2. 17-09-2026
    Last modifiedVulnerability information updated.

Description

SiYuan before v3.7.2 fails to escape the title-img Individual Attribute List value when rendering Gallery and Kanban cover images, allowing stored cross-site scripting via unescaped style attribute interpolation. Attackers with editor permissions can inject onload handlers that execute arbitrary code in the Electron renderer with full Node.js access when victims open affected documents.

CVSS metrics

4 scores · 2 sources · 2 versions

EPSS trend

Probability

0.54%

Chance of exploitation in the next 30 days

Percentile

45%

Versus all other CVEs

30-day change

Increase +0.17 pp

From 0.37% on 22-09-2026

22-09-202622-10-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Siyuan-note1 product

1 vendor · 1 product

References

2 links