# CVE-2021-4105: Unauthenticated Remote Code Execution on COSLAT Firewall

> Unauthenticated attackers can execute arbitrary code on COSLAT Firewall devices due to improper parameter handling.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 24 Feb 2023
- **Updated:** 18 May 2026
- **Also known as:** GHSA-gr7g-5rvj-cf96

## What is CVE-2021-4105?

CVE-2021-4105 is a critical code injection vulnerability in BG-TEK COSLAT Firewall, published on 24 Feb 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Improper Handling of Parameters vulnerability in BG-TEK COSLAT Firewall allows Remote Code Inclusion.

This issue affects COSLAT Firewall: from 5.24.0.R.20180630 before 5.24.0.R.20210727.

Weakness: CWE-755 (Improper Handling of Exceptional Conditions)

## Which versions are affected by CVE-2021-4105?

It affects 8 products.


Products: Bg-Tek Coslat Bx5s1d3 Firmware, Bg-Tek Coslat Bx5s1d4 Firmware, Bg-Tek Coslat Bx5s1d5 Firmware, Bg-Tek Coslat Rm1ds1000 Firmware, Bg-Tek Coslat Rm2ds2000 Firmware, Bg-Tek Coslat Rm2s200 Firmware, Bg-Tek Coslat Rm3s300 Firmware, Bg-Tek Coslat Rm4s500 Firmware.

## How do I fix CVE-2021-4105?

No fix has been published for CVE-2021-4105 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-4105 being exploited?

There is no known exploitation of CVE-2021-4105 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-4105 and fix it if it is affected.

What it is: CVE-2021-4105 is a critical code injection vulnerability in BG-TEK COSLAT Firewall, published on 24 Feb 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-4105 in the wild and no public exploit code.

Affected product: BG-TEK COSLAT Firewall. 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-2021-4105/ (Markdown: https://insights.sbomify.com/CVE-2021-4105/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-4105
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-4105
- OSV: https://osv.dev/vulnerability/CVE-2021-4105

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-4105/
Summaries are generated and may contain mistakes; the official description above is the record.