Time-of-check Time-of-use (TOCTOU) Race Condition in Notepad++ - #VU144989
Published: August 24, 2026
Vulnerability identifier: #VU144989
CSH Severity: Medium
CVSS v4: 8.4 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-367
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a local user to execute arbitrary code with administrator privileges.
The vulnerability exists due to a time-of-check time-of-use race condition in WinGup updater installer handling when verifying a downloaded installer by path and launching it after a user approval dialog. A local user can replace the verified installer file in %TEMP% before it is executed to execute arbitrary code with administrator privileges.
User interaction is required to perform a routine update and approve the resulting UAC prompt.
Affected software
Notepad++
Remediation
Install security update from vendor's website.
Notepad++ - update to 8.9.8