# CVE-2026-82649

## Summary

- **CVE ID:** CVE-2026-82649
- **Severity:** HIGH
- **CVSS Score:** 7 (CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N)
- **CWE:** CWE-427
- **Published:** Aug 30, 2026
- **Last Modified:** Sep 1, 2026

## Description

SiYuan Windows installer before version 3.8.1 (affected versions >= 2.0.14) contains an uncontrolled search path element vulnerability in its NSIS installer, which invokes system executables such as TASKKILL by name rather than by absolute path. Because NSIS nsExec::Exec resolves these calls using a search path that includes the installer's own launch directory ahead of System32, an attacker who plants a malicious executable (e.g., a renamed TASKKILL.exe) in that directory can have it executed when the installer runs. These calls occur in electron-builder's preInit hook before the license page is displayed, and with an all-users (elevated) install the planted binary executes with an elevated token, resulting in local privilege escalation.

## Affected Products

- siyuan-note — siyuan (2.0.14)
- siyuan-note — siyuan (3.8.1)

## References

- [CNA](https://github.com/siyuan-note/siyuan/security/advisories/GHSA-9j65-967f-5rv3)
- [CNA](https://github.com/siyuan-note/siyuan/commit/251596fc0de2f9528c00c224252fd073a99973f4)
- [CNA](https://www.vulncheck.com/advisories/siyuan-before-3.8.1-local-privilege-escalation-via-uncontrolled-search-path)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.12%
- **EPSS Percentile:** 2.2

---
_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-10._