Description

Security researcher Rocco Calvi disclosed a critical vulnerability in TP-Link AX1800 Wi-Fi 6 routers (Archer AX21/AX20) that allows attackers on the local network to achieve remote code execution as root. Tracked as CVE-2023-28760 and rated CVSS 7.5 (High), the flaw is rooted in the MiniDLNA service that powers the device’s media-sharing when a USB drive is attached. By default, Samba and FTP are enabled and Media Sharing starts automatically, exposing database on the shared USB. Any user with SMB or FTP access to that share can modify files.db, making the vulnerability reachable from the LAN even though the vendor initially assumed it would not be exploitable. The problem stems from improper bounds checking in MiniDLNA’s code: a callback that processes SQL query results copies metadata into a fixed-size stack buffer. Calvi showed that a crafted (DLNA profile name) The field in files.db can overflow that buffer, producing a stack-based buffer overflow. An attacker can chain the overflow into return-oriented programming (ROP) to bypass mitigations like ASLR and NX. The researchers located a “one gadget” leaving them able to redirect execution in the firmware, ultimately spawning an interactive root shell on the router a full compromise demonstrated live at Pwn2Own with a working proof-of-concept exploit. TP-Link was notified under coordinated disclosure and the issue was fixed in firmware version Archer AX20(EU)_V3_1.1.4 Build 20230219. Affected users should immediately update their router firmware and, if possible, disable media sharing or unmount USB storage until patched. Network operators should also restrict LAN access to shared storage, disable unnecessary services, and treat exposed home NAS/shares as high-risk attack surfaces.