CVE-2026-12221
Received Received - Intake
Stack-Based Buffer Overflow in Yealink SIP-T46U Firmware

Publication date: 2026-06-15

Last updated on: 2026-06-15

Assigner: VulDB

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.
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Meta Information
Published
2026-06-15
Last Modified
2026-06-15
Generated
2026-06-15
AI Q&A
2026-06-15
EPSS Evaluated
N/A
NVD
CVE-2026-12221
EUVD
EUVD-2026-36694
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
yealink sip-t46u 108.86.0.118
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-119 The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.
CWE-121 A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).
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Executive Summary

This vulnerability exists in the Yealink SIP-T46U device, specifically in the firmware component responsible for handling firmware chunk uploads. It involves the function sprintf in the /api/upgrade/upgrade file. By manipulating the arguments uid or start_offset, an attacker can cause a stack-based buffer overflow.

The attack requires the attacker to be within the local network to exploit this vulnerability. The exploit has been made public, meaning it is known and potentially usable by attackers.

Impact Analysis

Exploiting this vulnerability can lead to a stack-based buffer overflow, which may allow an attacker to execute arbitrary code, cause a denial of service, or gain elevated privileges on the affected device.

Since the vulnerability affects confidentiality, integrity, and availability (as indicated by the high CVSS scores), it can result in significant security risks including unauthorized access and disruption of services.

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