TI-2023-05149 Aliases CVE-2023-5593 GHSA-85wf-77c7-2h37

Out-of-bounds write in Zyxel SecuExtender SSL VPN Client

LOW 35CWE-787Published 2023-11-20 · Updated 2024-08-29

Key facts

Attack vector: Local
Privileges required: Low
User interaction: None
Attack complexity: Low
Impact type: Code execution
Confidentiality · integrity · availability: High · High · High
Fix status: No fix listed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-787 and the CVSS impact.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00216 12th percentileScored 2026-11-07

Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
Zyxel	SecuExtender SSL VPN Client	4.0.4.0	—	No fix listed	CNA

SecuExtender SSL VPN Client VendorZyxel Affected 4.0.4.0 Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:zyxel:secuextender_ssl_vpn:4.0.4.0:::::windows::	4.0.4.0	Vulnerable	Zyxel

cpe:2.3:a:zyxel:secuextender_ssl_vpn:4.0.4.0:*:*:*:*:windows:*:* Versions 4.0.4.0 Vulnerable ·Zyxel

Remediation

No fixed version listed by the sources yet.

Timeline

2026-10-02 Threatist record created from CVE-2023-5593
2026-10-03 Alias added: GHSA-85wf-77c7-2h37

References

Patch 1

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

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences