CVE-2026-12220 is a high-severity vulnerability (CVSS 8).
Summary
A vulnerability has been found in Yealink SIP-T46U 108.86.0.118. This affects the function mod_upgrade.SparePartsUpload of the file /api/upgrade/accupgradebychunk of the component Firmware Chunk Upload handler. Such manipulation of the argument uid leads to stack-based buffer overflow. The attack can only be initiated within the local network. The exploit has been disclosed to the public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.
Remediation
Apply the vendor’s update during your next patch window and verify exposure. Patch-management tools that can deploy and verify the fix include Action1, Automox, ManageEngine Patch Manager Plus, ManageEngine Endpoint Central. See our best patch management ranking.