2025-12-26

Authenticated command injection in the Yealink SIP-T21P_E2 IP phone (firmware 52.84.0.15) lets a remote user with normal, non-administrative privileges execute arbitrary operating-system commands by sending a crafted request to the ping utility of the diagnostic component. Because the CVSS vector reports PR:L, exploitation requires only a low-privileged authenticated session, and publicly available exploit code exists, though the EPSS probability remains modest at 0.60% (44th percentile) and the flaw is not listed in CISA KEV. Successful exploitation yields full high-impact compromise of confidentiality, integrity, and availability on the device.