LocalSystem code execution via unquoted service path
Published Jan 23, 2026 · Updated Jan 23, 2026
Privilege escalation in Softros Systems LogonExpert 8.1 allows local users to execute code as LocalSystem during service startup. LogonExpertSvc registers C:\Program Files\Softros Systems\LogonExpert\LogonExpertService.exe without quotation marks, so Windows searches earlier space-delimited executable candidates and runs an attacker-planted file. Exploitation requires local write access to an intermediate directory, and execution occurs when the automatic LocalSystem service starts.
Summary
What happened
Privilege escalation in Softros Systems LogonExpert 8.1 allows local users to execute code as LocalSystem during service startup. LogonExpertSvc registers C:\Program Files\Softros Systems\LogonExpert\LogonExpertService.exe without quotation marks, so Windows searches earlier space-delimited executable candidates and runs an attacker-planted file. Exploitation requires local write access to an intermediate directory, and execution occurs when the automatic LocalSystem service starts.
The record
- CVE
- CVE-2021-47890
- Published
- Jan 23, 2026
- Updated
- Jan 23, 2026
- Vendor
- Softros Systems
- Product
- LogonExpert
- Classifications
- CWE-428, T1574.009
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jan 23, 2026CVE publishedPublication date reported by the CVE source.
- Jan 23, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=8.1
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- LogonExpert 8.1 LogonExpertSvc Unquoted Service Pathproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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