CVE-2026-66396 json
SiYuan before v3.7.2 Stored XSS to RCE via title-img IAL
published 2026-07-27 3 mo ago modified 2026-10-24 15 d ago also EUVD-2026-49329
- cvss
- 8.4
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.5%
- EPSS 0.5% chance of exploitation in 30 days, percentile 45%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- siyuan-note siyuan 3.7.2
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- no
- Technical impact
- total
- Assessed
- 3 mo ago
Exploit prediction
0.54% chance of exploitation in the next 30 days, higher than 45% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- github.com https://github.com/siyuan-note/siyuan/security/advisories/GHSA-5rxg-wh59-mg34 referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 9.3 | CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H |
| CNA | 3.1 | 8.4 | CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:H |
| CNA | 4.0 | 9.3 | CVSS:4.0/AV:N/AC:L/AT:N/PR:H/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 |
Affected products
- siyuan-note siyuan
Classification
- Weakness
-
- CWE-79 Improper Neutralization of Input During Web Page Generation
References
-
github.com
/siyuan-note/siyuan/security/advisories/GHSA-5rxg-wh59-mg34
vendor-advisory, exploit
-
vulncheck.com
/advisories/siyuan-before-stored-xss-to-rce-via-title-img-ial
third-party-advisory
Sources
- CVE List CVE-2026-66396
- NVD CVE-2026-66396
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.