CVE-2026-12221

Severity CVSS v4.0:

HIGH

Type:

CWE-119 Buffer Errors

Publication date:

15/06/2026

Last modified:

15/06/2026

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 but did not respond in any way.

Impact

Vector 4.0

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 CVSS v4.0 Severity and Metrics:

Base Score: 7.30 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

Attack Vector (AV): Adjacent
Attack Complexity (AC): Low
Attack Requirements (AT): None
Privileges Required (PR): Low
User Interaction (UI): None
Confidentiality (VC): High
Integrity (VI): High
Availability (VA): High
Confidentiality (SC): None
Integrity (SI): None
Availability (SA): None
Exploit Maturity (E): POC

Base Score 4.0

7.30

Severity 4.0

HIGH

Vector 3.x

CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H CVSS v3.1 Severity and Metrics:

Base Score: 8.00 HIGH
Vector: CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Attack Vector (AV): Adjacent
Attack Complexity (AC): Low
Privileges Required (PR): Low
User Interaction (UI): None
Scope (S): Unchanged
Confidentiality (C): High
Integrity (I): High
Availability (A): High

Base Score 3.x

8.00

Severity 3.x

HIGH

Vector 2.0

AV:A/AC:L/Au:S/C:C/I:C/A:C CVSS v2.0 Severity and Metrics:

Base Score: 7.70 HIGH
Vector: AV:A/AC:L/Au:S/C:C/I:C/A:C

Attack Vector (AV): Adjacent
Attack Complexity (AC): Low
Authentication (Au): Single
Confidentiality (C): Complete
Integrity (I): Complete
Availability (A): Complete

Base Score 2.0

7.70

Severity 2.0

HIGH

CVE-2026-12221

Description

Impact

References to Advisories, Solutions, and Tools