# CVE-2020-4041: The filename of uploaded files vulnerable to stored XSS in Bolt CMS

> Stored XSS in Bolt CMS allows attackers to inject JavaScript via renamed uploaded files, potentially leading to code execution or account takeover.

- **Severity:** High 7.4 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 8 Jun 2020
- **Updated:** 4 Aug 2024
- **Also known as:** AZL-110321, GHSA-68q3-7wjp-7q3j

## What is CVE-2020-4041?

CVE-2020-4041 is a high-severity cross-site scripting vulnerability in bolt, published on 8 Jun 2020. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

In Bolt CMS before version 3.7.1, the filename of uploaded files was vulnerable to stored XSS. It is not possible to inject javascript code in the file name when creating/uploading the file. But, once created/uploaded, it can be renamed to inject the payload in it. Additionally, the measures to prevent renaming the file to disallowed filename extensions could be circumvented. This is fixed in Bolt 3.7.1.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2020-4041?

2 open source packages ship an affected version, including bolt/bolt. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `bolt/bolt` | Packagist | All versions | 3.7.1 |
| `bolt/bolt` | Packagist | All versions | 3.7.1 |

Products: Boltcms Bolt.

## How do I fix CVE-2020-4041?

Upgrade bolt/bolt to 3.7.1 or later.

## Is CVE-2020-4041 being exploited?

There is no known exploitation of CVE-2020-4041 in the wild and no public exploit code.

## Other vulnerabilities in bolt

- [CVE-2022-31321](https://insights.sbomify.com/CVE-2022-31321/): Path traversal in n/a (critical 9.1)
- [CVE-2019-10874](https://insights.sbomify.com/CVE-2019-10874/): Bolt Cross Site Request Forgery (CSRF) (high 8.8)
- [CVE-2019-9185](https://insights.sbomify.com/CVE-2019-9185/): Bolt Unrestricted Upload of File with Dangerous Type (high 8.8)
- [CVE-2020-4040](https://insights.sbomify.com/CVE-2020-4040/): CSRF issue on preview pages in Bolt CMS (high 8.6)
- [CVE-2025-34086](https://insights.sbomify.com/CVE-2025-34086/): Bolt CMS Authenticated Remote Code Execution via Profile Injection and File Rename (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-4041 and fix it if it is affected.

What it is: CVE-2020-4041 is a high-severity cross-site scripting vulnerability in bolt, published on 8 Jun 2020. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2020-4041 in the wild and no public exploit code.

Affected packages and fixed versions:
- bolt/bolt (Packagist): affected all versions; fixed in 3.7.1
- bolt/bolt (Packagist): affected all versions; fixed in 3.7.1

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-2020-4041/ (Markdown: https://insights.sbomify.com/CVE-2020-4041/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-4041
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-4041
- OSV: https://osv.dev/vulnerability/CVE-2020-4041

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-4041/
Summaries are generated and may contain mistakes; the official description above is the record.