# CVE-2024-56828: File upload in n/a

> Attackers can upload malicious files via the avatar endpoint due to missing extension validation, 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:** 6 Jan 2025
- **Updated:** 14 Jan 2025
- **Also known as:** GHSA-2423-2c9w-8vgr

## What is CVE-2024-56828?

CVE-2024-56828 is a critical vulnerability in n/a, published on 6 Jan 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

File Upload vulnerability in ChestnutCMS through 1.5.0. Based on the code analysis, it was determined that the /api/member/avatar API endpoint receives a base64 string as input. This string is then passed to the memberService.uploadAvatarByBase64 method for processing. Within the service, the base64-encoded image is parsed. For example, given a string like: data:image/html;base64,PGh0bWw+PGltZyBzcmM9eCBvbmVycm9yPWFsZXJ0KDEpPjwvaHRtbD4= the content after the comma is extracted and decoded using Base64.getDecoder().decode(). The substring from the 11th character up to the first occurrence of a semicolon (;) is assigned to the suffix variable (representing the file extension). The decoded content is then written to a file. However, the file extension is not validated, and since this functionality is exposed to the frontend, it poses significant security risks.

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

## Which versions are affected by CVE-2024-56828?

It affects 1 product.


Products: 1000mz Chestnutcms.

## How do I fix CVE-2024-56828?

No fix has been published for CVE-2024-56828 yet. Limit exposure of the affected software until one is available.

## Is CVE-2024-56828 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2024-56828 exists.

## Other vulnerabilities in n/a

- [CVE-2024-57450](https://insights.sbomify.com/CVE-2024-57450/): File upload in n/a (critical 9.8)
- [CVE-2024-57451](https://insights.sbomify.com/CVE-2024-57451/): Path traversal in n/a (high 7.5)
- [CVE-2024-57452](https://insights.sbomify.com/CVE-2024-57452/): Path traversal in n/a (high 7.5)
- [CVE-2025-70073](https://insights.sbomify.com/CVE-2025-70073/): Code injection in n/a (high 7.2)
- [CVE-2025-15009](https://insights.sbomify.com/CVE-2025-15009/): liweiyi ChestnutCMS Filename upload FilenameUtils.getExtension unrestricted upload (medium 5.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-56828 and fix it if it is affected.

What it is: CVE-2024-56828 is a critical vulnerability in n/a, published on 6 Jan 2025. 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-2024-56828 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-2024-56828/ (Markdown: https://insights.sbomify.com/CVE-2024-56828/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-56828
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-56828
- OSV: https://osv.dev/vulnerability/CVE-2024-56828

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-56828/
Summaries are generated and may contain mistakes; the official description above is the record.