# CVE-2026-25039: The application evaluate UNC path in workspace name

> Attackers can trigger NTLM hash disclosure or application hangs by using UNC paths in workspace names, affecting Parsec desktop users.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 20 Jul 2026
- **Updated:** 20 Jul 2026
- **Also known as:** GHSA-qx56-wxpm-j4m6

## What is CVE-2026-25039?

CVE-2026-25039 is a high-severity vulnerability in Scille parsec-cloud, published on 20 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Parsec is a cloud-based application for simple and cryptographically secure file sharing. The application does not sanitize the workspace name, creating a vulnerability if that workspace name is a UNC path. When creating mountpoint in the windows filesystem to mount the workspace of an organization, the application does not sanitize the workspace name. The cause issue if the workspace name evaluate to a UNC path since it's allowed for the name to containt `\` char. If the UNC path is invalid (or the targeted resource is not available) the application become unresponsive otherwise the system will interact with the mounted UNC path allowing the attacker to retrieve to [`NTLM`] hash.

Weakness: CWE-40 (Path Traversal: '\\UNC\share\name\' (Windows UNC Share))

## Which versions are affected by CVE-2026-25039?


## How do I fix CVE-2026-25039?

No fix has been published for CVE-2026-25039 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-25039 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-25039 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-25039 and fix it if it is affected.

What it is: CVE-2026-25039 is a high-severity vulnerability in Scille parsec-cloud, published on 20 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-25039 exists.

Affected product: Scille parsec-cloud. 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-2026-25039/ (Markdown: https://insights.sbomify.com/CVE-2026-25039/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-25039
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-25039
- OSV: https://osv.dev/vulnerability/CVE-2026-25039

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-25039/
Summaries are generated and may contain mistakes; the official description above is the record.