# CVE-2026-81931: Unrestricted upload of file with dangerous type in Prospero Flow CRM product photo allows stored cross-site scripting

> Authenticated users can upload malicious files to execute arbitrary JavaScript in the CRM application via stored XSS.

- **Severity:** Medium 4.8 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 27 Aug 2026
- **Updated:** 28 Aug 2026
- **Also known as:** GHSA-2g3f-q348-c747

## What is CVE-2026-81931?

CVE-2026-81931 is a medium-severity vulnerability in Roskus Prospero Flow CRM, published on 27 Aug 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

Unrestricted Upload of File with Dangerous Type in the product photo upload in Roskus Prospero Flow CRM before 5.16.0 allows an authenticated user holding the create product permission (routine Seller role) to execute arbitrary JavaScript in the application origin. The photo validation rule classifies the file only by its content (magic bytes) and rejects only a fixed list of PHP extensions, while ProductSaveController::save() names the stored file using the client-supplied extension and copies it into the public web root. A file that begins with an image header and carries an HTML extension passes validation, is stored under public/asset/upload/product/, and is served with a text/html content type, turning the upload into first-party stored script execution.

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

## Which versions are affected by CVE-2026-81931?


## How do I fix CVE-2026-81931?

No fix has been published for CVE-2026-81931 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-81931 being exploited?

There is no known exploitation of CVE-2026-81931 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-81931 and fix it if it is affected.

What it is: CVE-2026-81931 is a medium-severity vulnerability in Roskus Prospero Flow CRM, published on 27 Aug 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-81931 in the wild and no public exploit code.

Affected product: Roskus Prospero Flow CRM. 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-2026-81931/ (Markdown: https://insights.sbomify.com/CVE-2026-81931/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-81931
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-81931
- OSV: https://osv.dev/vulnerability/CVE-2026-81931

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-81931/
Summaries are generated and may contain mistakes; the official description above is the record.