Vulnerability · Published Sep 9, 2026 · Assigned by VulnCheck
CVE-2026-87811SiYuan before v3.8.2 Stored XSS via notebook template paths
High 7.3
In plain English
A high-severity cross-site scripting in siyuan from siyuan-note. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 31% of all known vulnerabilities).
Severity (CVSS 3.1)7.3High
Exploit odds (30 days)0.4%top 69.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known
Official description
SiYuan before v3.8.2 inserts persisted notebook template paths into HTML input value attributes without proper attribute encoding. Attackers can craft malicious template paths that break out of the attribute context and execute JavaScript when a victim opens notebook configuration, enabling same-origin API requests and application state manipulation.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| siyuan-note | siyuan | 0 – before 3.8.2 |
Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N
References
- GitHub Security Advisory (GHSA-v6wf-r2gr-rrgf) vendor-advisory
- VulnCheck Advisory: SiYuan before v3.8.2 Stored XSS via notebook template paths third-party-advisory