# CVE-2020-35729: Command injection in n/a

> An attacker can execute arbitrary OS commands via shell metacharacters in the user parameter of the authentication script.

- **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:** 27 Dec 2020
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-w4v7-6457-x826

## What is CVE-2020-35729?

CVE-2020-35729 is a critical command injection vulnerability in n/a, published on 27 Dec 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

KLog Server 2.4.1 allows OS command injection via shell metacharacters in the actions/authenticate.php user parameter.

Weakness: CWE-78 (Improper Neutralization of Special Elements used in an OS Command)

## Which versions are affected by CVE-2020-35729?

It affects 1 product.


Products: Klogserver Klog Server.

## How do I fix CVE-2020-35729?

No fix has been published for CVE-2020-35729 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-35729 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2020-35729 exists.

Public exploit code:

- CVE-2020-35729 (github_poc): https://github.com/Al1ex/CVE-2020-35729
- Klog Server authenticate.php user Unauthenticated Command Injection (metasploit)
- Klog Server 2.4.1 - Command Injection (Unauthenticated) (exploitdb)
- Klog Server 2.4.1 - Unauthenticated Command Injection (Metasploit) (exploitdb)
- Klog Server <=2.41 - Unauthenticated Command Injection (nuclei): http/cves/2020/CVE-2020-35729.yaml

## Other vulnerabilities in n/a

- [CVE-2021-3317](https://insights.sbomify.com/CVE-2021-3317/): Command injection in n/a (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-35729 and fix it if it is affected.

What it is: CVE-2020-35729 is a critical command injection vulnerability in n/a, published on 27 Dec 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2020-35729 exists.

Affected product: n/a. 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-2020-35729/ (Markdown: https://insights.sbomify.com/CVE-2020-35729/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-35729
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-35729
- OSV: https://osv.dev/vulnerability/CVE-2020-35729

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-35729/
Summaries are generated and may contain mistakes; the official description above is the record.