CVE-2021-40556 — HIGH (8.8)

Vulnerability Description

A stack overflow vulnerability exists in the httpd service in ASUS RT-AX56U Router Version 3.0.0.4.386.44266. This vulnerability is caused by the strcat function called by "caupload" input handle function allowing the user to enter 0xFFFF bytes into the stack. This vulnerability allows an attacker to execute commands remotely. The vulnerability requires authentication.

CVSS Score

8.8

HIGH

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality

HIGH

Integrity

HIGH

Availability

HIGH

Affected Products

Vendor	Product	Versions
Asus	Rt-Ax56U Firmware	3.0.0.4.386.44266
Asus	Rt-Ax56U	-

Related Weaknesses (CWE)

CWE-787

References

https://www.asus.com/tw/Networking-IoT-Servers/WiFi-Routers/ASUS-WiFi-Routers/RTProductVendor Advisory
https://x1ng.top/2021/10/14/ASUS%E6%A0%88%E6%BA%A2%E5%87%BA%E6%BC%8F%E6%B4%9E%E5ExploitThird Party Advisory
https://www.asus.com/tw/Networking-IoT-Servers/WiFi-Routers/ASUS-WiFi-Routers/RTProductVendor Advisory
https://x1ng.top/2021/10/14/ASUS%E6%A0%88%E6%BA%A2%E5%87%BA%E6%BC%8F%E6%B4%9E%E5ExploitThird Party Advisory

FAQ

What is CVE-2021-40556?

CVE-2021-40556 is a vulnerability with a CVSS score of 8.8 (HIGH). A stack overflow vulnerability exists in the httpd service in ASUS RT-AX56U Router Version 3.0.0.4.386.44266. This vulnerability is caused by the strcat function called by "caupload" input handle func...

How severe is CVE-2021-40556?

CVE-2021-40556 has been rated HIGH with a CVSS base score of 8.8/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2021-40556?

Check the references section above for vendor advisories and patch information. Affected products include: Asus Rt-Ax56U Firmware, Asus Rt-Ax56U.