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Vulnerability · Published Jun 15, 2026 · Assigned by VulDB

CVE-2026-12221Yealink SIP-T46U Firmware Chunk Upload upgrade sprintf stack-based overflow

High 8.0

In plain English

A high-severity stack buffer overflow in SIP-T46U from Yealink. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 31% of all known vulnerabilities).

Severity (CVSS 3.1)8.0High
Exploit odds (30 days)0.4%top 68.8% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

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.

Affected products (as reported)

VendorProductVersions
Yealink SIP-T46U 108.86.0.118

Weakness: CWE-121, CWE-119 · Vector: CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:X/RC:C

References