ASUS RT-AX55、RT-AX56U_V2 - Format String - 3
Priority LOW 36CWE-134Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- High
- 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-134 and the CVSS impact.
Summary
It is identified a format string vulnerability in ASUS RT-AX56U V2’s iperf client function API. This vulnerability is caused by lacking validation for a specific value within its set_iperf3_cli.cgi module. A remote attacker with administrator privilege can exploit this vulnerability to perform remote arbitrary code execution, arbitrary system operation or disrupt service.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.0128 70th 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 |
|---|---|---|---|---|---|
| ASUS | RT-AX55 | 3.0.0.4.386_50460 | — | No fix listed | CNA |
| ASUS | RT-AX56U_V2 | 3.0.0.4.386_50460 | — | No fix listed | CNA |
- RT-AX55 VendorASUS Affected 3.0.0.4.386_50460 Fixed in — No fix listed CNA
- RT-AX56U_V2 VendorASUS Affected 3.0.0.4.386_50460 Fixed in — No fix listed CNA
CPE configurations NVD · 6
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:asus:rt-ax55_firmware:3.0.0.4.386_50460:*:*:*:*:*:*:* | 3.0.0.4.386_50460 | Vulnerable | ASUS |
| cpe:2.3:h:asus:rt-ax55:-:*:*:*:*:*:*:* | not specified by NVD | Running on | ASUS |
| cpe:2.3:o:asus:rt-ax56u_v2_firmware:3.0.0.4.386_50460:*:*:*:*:*:*:* | 3.0.0.4.386_50460 | Vulnerable | ASUS |
| cpe:2.3:h:asus:rt-ax56u_v2:-:*:*:*:*:*:*:* | not specified by NVD | Running on | ASUS |
| cpe:2.3:o:asus:rt-ac86u_firmware:3.0.0.4_386_51529:*:*:*:*:*:*:* | 3.0.0.4_386_51529 | Vulnerable | ASUS |
| cpe:2.3:h:asus:rt-ac86u:-:*:*:*:*:*:*:* | not specified by NVD | Running on | ASUS |
- cpe:2.3:o:asus:rt-ax55_firmware:3.0.0.4.386_50460:*:*:*:*:*:*:* Versions 3.0.0.4.386_50460 Vulnerable ·ASUS
- cpe:2.3:h:asus:rt-ax55:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·ASUS
- cpe:2.3:o:asus:rt-ax56u_v2_firmware:3.0.0.4.386_50460:*:*:*:*:*:*:* Versions 3.0.0.4.386_50460 Vulnerable ·ASUS
- cpe:2.3:h:asus:rt-ax56u_v2:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·ASUS
- cpe:2.3:o:asus:rt-ac86u_firmware:3.0.0.4_386_51529:*:*:*:*:*:*:* Versions 3.0.0.4_386_51529 Vulnerable ·ASUS
- cpe:2.3:h:asus:rt-ac86u:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·ASUS
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2023-39240
- 2026-10-03 Alias added: GHSA-pjc4-2x49-3j92
References
More ASUS Rt-ac86u Firmware vulnerabilities
- TI-2023-17556 ASUS RT-AX56U V2 & RT-AC86U - Format String -1 CVSS 3.1HIGH 7.2
- TI-2023-17557 ASUS RT-AX56U V2 & RT-AC86U - Format String - 2 CVSS 3.1CRITICAL 9.8
- TI-2021-02220 In ASUS RT-AX3000, ZenWiFi AX (XT8), RT-AX88U, and other ASUS routers with firmware <… CVSS 3.1HIGH 7.5
- TI-2018-06370 ASUS RT-AC51U, RT-AC58U, RT-AC66U, RT-AC1750, RT-ACRH13, and RT-N12 D1 routers with… CVSS 3.0CRITICAL 9.8
- TI-2018-06731 Main_Analysis_Content.asp in /apply.cgi on ASUS RT-AC66U, RT-AC68U, RT-AC86U, RT-AC88U… CVSS 3.0CRITICAL 9.8
- TI-2023-20391 ASUS RT-AC86U - Command injection vulnerability - 5 CVSS 3.1HIGH 8.8
Sources
- CVE-2023-39240 · CVE Program
- CVE-2023-39240 · NVD
- FIRST EPSS
- GHSA-pjc4-2x49-3j92 · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences