# CVE-2021-47890: LogonExpert 8.1 - 'LogonExpertSvc' Unquoted Service Path

> Attackers can exploit an unquoted service path in LogonExpert to execute malicious code with LocalSystem privileges during service startup.

- **Severity:** High 8.5 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 23 Jan 2026
- **Updated:** 23 Jan 2026
- **Also known as:** GHSA-6xfm-hcmf-ch35

## What is CVE-2021-47890?

CVE-2021-47890 is a high-severity vulnerability in Softros Systems LogonExpert, published on 23 Jan 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

LogonExpert 8.1 contains an unquoted service path vulnerability in the LogonExpertSvc service running with LocalSystem privileges. Attackers can exploit the unquoted path to place malicious executables in intermediate directories, potentially gaining elevated system access during service startup.

Weakness: CWE-428 (Unquoted Search Path or Element)

## Which versions are affected by CVE-2021-47890?


## How do I fix CVE-2021-47890?

No fix has been published for CVE-2021-47890 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-47890 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-47890 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-47890 and fix it if it is affected.

What it is: CVE-2021-47890 is a high-severity vulnerability in Softros Systems LogonExpert, published on 23 Jan 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-47890 exists.

Affected product: Softros Systems LogonExpert. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2021-47890/ (Markdown: https://insights.sbomify.com/CVE-2021-47890/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-47890
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-47890
- OSV: https://osv.dev/vulnerability/CVE-2021-47890

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-47890/
Summaries are generated and may contain mistakes; the official description above is the record.