# CVE-2017-7393: Use after free in n/a

> An authenticated client can trigger a double free in TigerVNC, causing denial of service or potential code execution.

- **Severity:** High 8.8 (`CVSS:3.0/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:** Yes
- **Published:** 1 Apr 2017
- **Updated:** 5 Aug 2024
- **Also known as:** DEBIAN-CVE-2017-7393, GHSA-6qmp-qcvf-x3pr

## What is CVE-2017-7393?

CVE-2017-7393 is a high-severity use after free vulnerability in n/a, published on 1 Apr 2017. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

In TigerVNC 1.7.1 (VNCSConnectionST.cxx VNCSConnectionST::fence), an authenticated client can cause a double free, leading to denial of service or potentially code execution.

Weakness: CWE-415 (Double Free)

## Which versions are affected by CVE-2017-7393?

It affects 1 product.


Products: Tigervnc Tigervnc.

## How do I fix CVE-2017-7393?

Apply the vendor's patch.

## Is CVE-2017-7393 being exploited?

There is no known exploitation of CVE-2017-7393 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2014-0011](https://insights.sbomify.com/CVE-2014-0011/): Memory corruption in TigerVNC (critical 9.8)
- [CVE-2017-5581](https://insights.sbomify.com/CVE-2017-5581/): Memory corruption in n/a (critical 9.8)
- [CVE-2026-34352](https://insights.sbomify.com/CVE-2026-34352/): Missing authorization in TigerVNC (high 8.5)
- [CVE-2017-7392](https://insights.sbomify.com/CVE-2017-7392/): Denial of service in n/a (high 7.5)
- [CVE-2017-7394](https://insights.sbomify.com/CVE-2017-7394/): Denial of service in n/a (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2017-7393 and fix it if it is affected.

What it is: CVE-2017-7393 is a high-severity use after free vulnerability in n/a, published on 1 Apr 2017. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2017-7393 in the wild and no public exploit code.

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-2017-7393/ (Markdown: https://insights.sbomify.com/CVE-2017-7393/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-7393
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-7393
- OSV: https://osv.dev/vulnerability/CVE-2017-7393

---
From sbomify Insights: https://insights.sbomify.com/CVE-2017-7393/
Summaries are generated and may contain mistakes; the official description above is the record.