High severity8.8NVD Advisory· Published Oct 6, 2022· Updated Jun 17, 2026
CVE-2021-40556
CVE-2021-40556
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.
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Affected products
3- cpe:2.3:o:asus:rt-ax56u_firmware:3.0.0.4.386.44266:*:*:*:*:*:*:*
(expand)+ 1 more
- (no CPE)
- (no CPE)range: 3.0.0.4.386.44266
Patches
Vulnerability mechanics
References
2- x1ng.top/2021/10/14/ASUS%E6%A0%88%E6%BA%A2%E5%87%BA%E6%BC%8F%E6%B4%9E%E5%88%86%E6%9E%90/nvdExploitThird Party Advisory
- www.asus.com/tw/Networking-IoT-Servers/WiFi-Routers/ASUS-WiFi-Routers/RT-AX56U/HelpDesk_BIOS/nvdProductVendor Advisory
News mentions
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