Security Vulnerability CVE-2023-33009 - Complete Analysis and Details

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CVE-2023-33009

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National Vulnerability Database Information

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 Base Score: 9.8 (v3.1)

The **CVSS Base Score** is a score from **0 to 10** that represents the intrinsic severity of a vulnerability. A higher score indicates greater severity.

Value

0.02.55.07.510.0

Published on: 05/24/2023 13:15:09
Last modified: 10/27/2025 17:04:58
NIST: CVE source from the National Vulnerability Database (NVD)

CVSS Metrics Details

Base Severity: CRITICAL
Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack Vector: NETWORK
Attack Complexity: LOW
Privileges Required: NONE
User Interaction: NONE
Scope: UNCHANGED
Confidentiality Impact: HIGH
Integrity Impact: HIGH
Availability Impact: HIGH

Common Weakness Enumeration (CWE)

Database CWE: v4.18

CWE-120: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') ↗

The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer.

Fonte: MITRE CWE

FIRST Information

EPSS Score: 0.0617

The **EPSS (Exploit Prediction Scoring System)** is a score from **0 to 1** that indicates the **probability** that a vulnerability will be exploited in the real world in the next 30 days. A higher value indicates a greater likelihood of exploitation.

Value

0.00.250.50.751.0

Percentile: 0.9047

The **Percentile** indicates how much higher this vulnerability's EPSS score is compared to all other vulnerabilities in the EPSS database. For example, a percentile of 0.90 (90%) means that 90% of vulnerabilities have an EPSS score equal to or lower than the current one.

Value

0.00.250.50.751.0

*Data updated as of: 2025-12-13

CISA Information (Known Exploited Vulnerabilities)

The **CISA KEV Catalog** lists vulnerabilities that have been **actively exploited in the real world**. If a CVE is present in this catalog, it indicates that the threat is immediate and mitigation should be a top priority.

CVE **CVE-2023-33009** **IS PRESENT** in the CISA KEV Catalog!

Vulnerability Name: Zyxel Multiple Firewalls Buffer Overflow Vulnerability
Short Description: Zyxel ATP, USG FLEX, USG FLEX 50(W), USG20(W)-VPN, VPN, and ZyWALL/USG firewalls contain a buffer overflow vulnerability in the notification function that could allow an unauthenticated attacker to cause denial-of-service (DoS) conditions and remote code execution on an affected device.
Date Added to KEV: 06/05/2023
Vendor/Product: Zyxel / Multiple Firewalls
Required Action: Apply updates per vendor instructions.
Due Date: 06/26/2023

Articles published on Red Hot Cyber

NVD References

Exploit PoC from GitHub

No results found on GitHub for this CVE.