CVE-2026-82649

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.

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Weakness Type (CWE)

CWE-427 CWE-427

References

Other References

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

Frequently Asked Questions

What is CVE-2026-82649? +

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.

How do I check if I'm vulnerable to CVE-2026-82649? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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