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CVE-2023-33009

Published: May 24, 2023Updated: Feb 26, 2026 Sources: CVE List NVD BDUCWE-120
NVD MITRE
9.8CVSSCRITICAL
EPSS Score
28.1%
Top 2.1%
CISA KEV
Active Exploitation
Since Jun 5, 2023
Exploits
No Known Exploits
Remediation
Patch Available

Description

A buffer overflow vulnerability in the notification function in Zyxel ATP series firmware versions 4.60 through 5.36 Patch 1, USG FLEX series firmware versions 4.60 through 5.36 Patch 1, USG FLEX 50(W) firmware versions 4.60 through 5.36 Patch 1, USG20(W)-VPN firmware versions 4.60 through 5.36 Patch 1, VPN series firmware versions 4.60 through 5.36 Patch 1, ZyWALL/USG series firmware versions 4.60 through 4.73 Patch 1, could allow an unauthenticated attacker to cause denial-of-service (DoS) conditions and even a remote code execution on an affected device.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:HI:HA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:HAvailability
High
Open in CVSS calculator →

Weaknesses

CWE-120

Affected Products

atp100 firmwarezyxelNetworking Infrastructure
atp200 firmwarezyxelNetworking Infrastructure
atp500 firmwarezyxelNetworking Infrastructure
atp100w firmwarezyxelNetworking Infrastructure
atp700 firmwarezyxelNetworking Infrastructure
zyxelcommercialTWNetworking Infrastructureaka zyxel communications corp.
and 31 more affected products View all →

Attack Graph

Products CVE Techniques Tactics

Click technique nodes to view MITRE ATT&CK details. Scroll to zoom, drag to pan.

Exploitability

CISA Known Exploited Vulnerability
Added to KEV:Jun 5, 2023
Remediation due:Jun 26, 2023

Required action: Apply updates per vendor instructions.

Official Patch Available

MITRE ATT&CK

2 techniques
Initial Access
Privilege Escalation
View detailed technique mapping

References

https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-multiple-buffer-overflow-vulnerabilities-of-firewalls
zyxel.com
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-33009
cisa.gov

Timeline

Published
May 24, 2023
Added to CISA KEV
Jun 5, 2023
Last Updated
Feb 26, 2026

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