CVE-2026-12221
Yealink SIP-T46U Firmware Chunk Upload upgrade sprintf stack-based overflow
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.
INFO
Published Date :
June 15, 2026, 6:16 a.m.
Last Modified :
June 15, 2026, 6:16 a.m.
Remotely Exploit :
No
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-12221
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 2.0 | HIGH | [email protected] | ||||
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 4.0 | HIGH | [email protected] |
Solution
- Update the firmware to the latest version.
- Restrict access to the upgrade API.
- Validate user input for uid and start_offset.
- Sanitize arguments before passing to sprintf.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-12221.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-12221 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-12221
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-12221 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-12221 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Jun. 15, 2026
Action Type Old Value New Value Added 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. Added CVSS V4.0 AV:A/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CVSS V3.1 AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Added CVSS V2 (AV:A/AC:L/Au:S/C:C/I:C/A:C) Added CWE CWE-119 Added CWE CWE-121 Added Reference http://cdn2.v50to.cc/T46U/T46U_mod_upgrade_Upgrade_chunk_stack_overflow.zip Added Reference https://vuldb.com/cve/CVE-2026-12221 Added Reference https://vuldb.com/submit/834207 Added Reference https://vuldb.com/vuln/370864 Added Reference https://vuldb.com/vuln/370864/cti