CVE-2026-12221
HighCVSS 8.0Exploitation Probability (EPSS)
Low risk30th percentile - higher than 30% of all known CVEs
Summary
Vulnerability in Yealink SIP-T46U version 108.86.0.118 in the Firmware Chunk Upload Handler component (sprintf function in /api/upgrade/upgrade). Manipulation of uid/start_offset arguments leads to stack-based buffer overflow. Attack requires local network access.
Risk Assessment
Risk includes remote code execution or device crash, potentially disrupting VoIP communication.
Recommendation
Restrict access to the firmware upgrade interface; apply the Yealink patch when released.
Other vulnerabilities in Yealink SIP-T46U
See all- CVE-2026-12223Medium
A vulnerability in Yealink SIP-T46U 108.86.0.118. The mod_webd.TFTPUploadIperf function in /api/inner/tftpuploadiperf of the Web FastCGI Service component allows command injection via ip/port arguments. Local network attack, exploit public. Fixed in version 108.87.0.23.
- CVE-2026-12222High
Vulnerability in Yealink SIP-T46U version 108.86.0.118 in the Web FastCGI Service component (mod_webd.BlueToothTest function in /api/inner/bttest). Manipulation of btMac/pin/reserved arguments leads to stack-based buffer overflow. Attack requires local network access.
- CVE-2026-12220High
Vulnerability in Yealink SIP-T46U version 108.86.0.118 in the Firmware Chunk Upload Handler component (mod_upgrade.SparePartsUpload function in /api/upgrade/accupgradebychunk). Manipulation of uid argument leads to stack-based buffer overflow. Attack requires local network access.
- CVE-2026-12219Medium
A vulnerability has been found in Yealink SIP-T46U version 108.86.0.118, allowing command injection in the mod_diagnose.CommandShellByType function of /api/diagnosis/start. The attack can be launched remotely by manipulating the Time argument. The issue is fixed in version 108.87.0.23.
- CVE-2026-12218High
Vulnerability in Yealink SIP-T46U version 108.87.50.1 in the Web FastCGI Service component (StartReportInformation function in /api/inner/beforewifitest). Manipulation of port argument leads to stack-based buffer overflow. Attack requires local network access.
Original NVD description (English source)
A vulnerability was found in Yealink SIP-T46U 108.86.0.118. This impacts the function sprintf of the file /api/upgrade/upgrade of the component Firmware Chunk Upload Handler. Performing a manipulation of the argument uid/start_offset results in stack-based buffer overflow. The attack needs to be approached within the local network. The exploit has been made public and could be used. The vendor was contacted early about this disclosure and is working on a patch to fix it.