What is the CVSS score of CVE-2023-39238?

CVE-2023-39238 has a CVSS 3.1 base score of 7.2 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 1.2%.

Rt Ax55 Firmware CVE-2023-39238

HIGH

Use of Externally-Controlled Format String (CWE-134)

2023-09-07 twcert@cert.org.tw

RCE Rt Ax55 Firmware Rt Ax56U V2 Firmware Rt Ac86U Firmware Asus

7.2

CVSS 3.1 · Vendor: cert

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Vulnerability Assessment

Weakness	CWE CWE-134 OWASP Top 10:2025 A05:2025 - Injection ASVS 5.0 V1 - Encoding and Sanitization Format string safety
Impact	CVSS score of 7.2 (HIGH). Attack characteristics: network attack vector, low complexity, high privileges required, no user interaction not required.
Exploit ScenarioDerived	This vulnerability can be exploited remotely over the network. Successful exploitation could compromise the high-severity affected system.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).

No patch listed yet 1.2% exploitation probability (EPSS)

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AnalysisAI

It is identified a format string vulnerability in ASUS RT-AX56U V2. Rated high severity (CVSS 7.2), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.

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Technical ContextAI · show details

This vulnerability is classified under CWE-134. It is identified a format string vulnerability in ASUS RT-AX56U V2. This vulnerability is caused by lacking validation for a specific value within its set_iperf3_svr.cgi module. A remote attacker with administrator privilege can exploit this vulnerability to perform remote arbitrary code execution, arbitrary system operation or disrupt service. Affected products include: Asus Rt-Ax55 Firmware, Asus Rt-Ax56U V2 Firmware, Asus Rt-Ac86U Firmware.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (cert) PRIMARY 7.2 HIGH

AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

Primary rating from Vendor (cert) · only source for this CVE.

CVSS VectorVendor: cert

Attack Vector

Network

Attack Complexity

Low

Privileges Required

High

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

DescriptionCVE.org

It is identified a format string vulnerability in ASUS RT-AX56U V2. This vulnerability is caused by lacking validation for a specific value within its set_iperf3_svr.cgi module. A remote attacker with administrator privilege can exploit this vulnerability to perform remote arbitrary code execution, arbitrary system operation or disrupt service.

Threat Intelligence Overview

EPSS Score

1.2%

Top 36% exploitable

Data Quality

2 sources

Confidence: Low

NVD

CVE.org

EPSS

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity HIGH

CISA KEV No

Public POC No

EPSS 1.2%

Patch available No

Active threat No

Deciding rule

HIGH severity (CVSS 7.0-8.9)

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived

Scheduled

Exploitation· derived

None

System Exposure· derived

Open

Automatable· derived

Human Impact· derived

Medium

Priority Score

Low Medium High Critical

KEV: 0

EPSS: +1

CVSS: +36

PoC: 0

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Remote Code Execution CRITICAL

Remote Code Execution represents the critical moment when an attacker successfully runs arbitrary code on a target system without physical access.

Affected Products (CPE)CVE.org

cpe:2.3:o:asus:rt-ax55_firmware:3.0.0.4.386_50460:*:*:*:*:*:*:*

cpe:2.3:o:asus:rt-ax56u_v2_firmware:3.0.0.4.386_50460:*:*:*:*:*:*:*

cpe:2.3:o:asus:rt-ac86u_firmware:3.0.0.4_386_51529:*:*:*:*:*:*:*

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References

Advisories & patches

REF https://www.twcert.org.tw/tw/cp-132-7354-4e654-1.html

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