# CVE-2023-5593: Memory corruption in SecuExtender SSL VPN Client

> An authenticated local user can escalate privileges via an out-of-bounds write in the Zyxel SecuExtender SSL VPN Client.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/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:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 20 Nov 2023
- **Updated:** 29 Aug 2024
- **Also known as:** GHSA-85wf-77c7-2h37

## What is CVE-2023-5593?

CVE-2023-5593 is a high-severity memory corruption vulnerability in Zyxel SecuExtender SSL VPN Client, published on 20 Nov 2023. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

The out-of-bounds write vulnerability in the Windows-based SecuExtender SSL VPN Client software version 4.0.4.0 could allow an authenticated local user to gain a privilege escalation by sending a crafted CREATE message.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2023-5593?

It affects 1 product.


Products: Zyxel Secuextender Ssl Vpn.

## How do I fix CVE-2023-5593?

No fix has been published for CVE-2023-5593 yet. Limit exposure of the affected software until one is available.

## Is CVE-2023-5593 being exploited?

There is no known exploitation of CVE-2023-5593 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-5593 and fix it if it is affected.

What it is: CVE-2023-5593 is a high-severity memory corruption vulnerability in Zyxel SecuExtender SSL VPN Client, published on 20 Nov 2023. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2023-5593 in the wild and no public exploit code.

Affected product: Zyxel SecuExtender SSL VPN Client. 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-2023-5593/ (Markdown: https://insights.sbomify.com/CVE-2023-5593/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-5593
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-5593
- OSV: https://osv.dev/vulnerability/CVE-2023-5593

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-5593/
Summaries are generated and may contain mistakes; the official description above is the record.