CVE-2026-12221CWE-119CWE-121

Yealink SIP-T46U Firmware Chunk Upload upgrade sprintf stack-based overflow

High · published June 15, 2026

CVSS v4.0
8.6
EPSS
0%
Percentile
29.8
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
8.6 · HIGH
Vector
CVSS:4.0/AV:A/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P
EPSS
0.00371 · 29.8th percentile
Weaknesses
CWE-119 · Improper Restriction of Operations within the Bounds of a Memory Buffer; CWE-121 · Stack-based Buffer Overflow
Published
2026-06-15T05:00Z
EPSS history
Timeline
  • 15 JUN 05:00Z
    Yealink SIP-T46U Firmware Chunk Upload upgrade sprintf stack-based overflow
    cvelistv5