VDB-230163 · CVE-2023-27988 · EUVD-2023-31713

ZyXEL NAS326 5.21 os command injection

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
7.0	$0-$5k	0.00

Summaryinfo

A vulnerability has been found in ZyXEL NAS326 and classified as critical. Affected is an unknown function. Performing a manipulation results in os command injection. This vulnerability was named CVE-2023-27988. The attack may be initiated remotely. There is no available exploit. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in ZyXEL NAS326. It has been classified as critical. This affects an unknown part. The manipulation with an unknown input leads to a os command injection vulnerability. CWE is classifying the issue as CWE-78. The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

The post-authentication command injection vulnerability in the Zyxel NAS326 firmware versions prior to V5.21(AAZF.13)C0 could allow an authenticated attacker with administrator privileges to execute some operating system (OS) commands on an affected device remotely.

The weakness was presented 05/30/2023. It is possible to read the advisory at zyxel.com. This vulnerability is uniquely identified as CVE-2023-27988 since 03/09/2023. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1202 according to MITRE ATT&CK.

Upgrading to version 5.21(AAZF.13)C0 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2023-31713). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Vendor

ZyXEL

Name

NAS326

Version

5.21

License

commercial

Website

Vendor: https://www.zyxel.com/

CPE 2.3info

🔍

CPE 2.2info

🔍

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.2
VulDB Meta Temp Score: 7.1

VulDB Base Score: 7.2
VulDB Temp Score: 6.9
VulDB Vector: 🔍
VulDB Reliability: 🔍

CNA Base Score: 7.2
CNA Vector (Zyxel Corporation): 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

Exploitinginfo

Class: Os command injection
CWE: CWE-78 / CWE-77 / CWE-74
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Upgrade: NAS326 5.21(AAZF.13)C0

Timelineinfo

03/09/2023 🔍
05/30/2023 +81 days 🔍
05/30/2023 +0 days 🔍
12/01/2025 +916 days 🔍

Sourcesinfo

Vendor: zyxel.com

Advisory: zyxel.com
Status: Confirmed

CVE: CVE-2023-27988 (🔍)
GCVE (CVE): GCVE-0-2023-27988
GCVE (VulDB): GCVE-100-230163
EUVD: 🔍

Entryinfo

Created: 05/30/2023 06:40
Updated: 12/01/2025 03:38
Changes: 05/30/2023 06:40 (48), 12/01/2025 03:38 (17)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.