# CVE-2021-27964: File upload in n/a

> Unauthenticated attackers can upload arbitrary files via an unprotected endpoint, potentially leading to remote code execution.

- **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:** 5 Mar 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-mxm8-cmpq-g5cx

## What is CVE-2021-27964?

CVE-2021-27964 is a critical vulnerability in n/a, published on 5 Mar 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

SonLogger before 6.4.1 is affected by Unauthenticated Arbitrary File Upload. An attacker can send a POST request to /Config/SaveUploadedHotspotLogoFile without any authentication or session header. There is no check for the file extension or content of the uploaded file.

Weakness: CWE-434 (Unrestricted Upload of File with Dangerous Type)

## Which versions are affected by CVE-2021-27964?

It affects 1 product.


Products: Sfcyazilim Sonlogger.

## How do I fix CVE-2021-27964?

No fix has been published for CVE-2021-27964 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-27964 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-27964 exists.

Public exploit code:

- SonLogger 4.2.3.3 - Unauthenticated Arbitrary File Upload (Metasploit) (exploitdb)
- SonLogger - Arbitrary File Upload (nuclei): http/cves/2021/CVE-2021-27964.yaml

## Other vulnerabilities in n/a

- [CVE-2021-27963](https://insights.sbomify.com/CVE-2021-27963/): Missing authorization in n/a (high 8.2)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-27964 and fix it if it is affected.

What it is: CVE-2021-27964 is a critical vulnerability in n/a, published on 5 Mar 2021. 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-2021-27964 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-2021-27964/ (Markdown: https://insights.sbomify.com/CVE-2021-27964/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-27964
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-27964
- OSV: https://osv.dev/vulnerability/CVE-2021-27964

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-27964/
Summaries are generated and may contain mistakes; the official description above is the record.