CVE-2026-66396

SiYuan before v3.7.2 Stored XSS to RCE via title-img IAL

HIGH
8.4
CVSS Score
Published: July 27, 2026 at 03:43 PM UTC
Updated: October 24, 2026 at 01:10 PM UTC
2 products affected across 2 vendorsSiyuanSiyuan

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Severity
HIGH8.4
Exploit prediction
EPSS 0.5%
SSVC
PoC

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 3.7.2
Affected range stops below 3.7.2, so it looks safe — our inference, not a vendor statement
0 ≤ v < 3.7.20
Vendor states this is fixed in 3.7.2 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCPoCNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.4HIGHVulnCheck
Attack Vector
NETWORK
Complexity
LOW
Privileges
HIGH
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-79

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