High severity · published Jun 15, 2026
CVE-2026-12221
Yealink SIP-T46U Firmware Chunk Upload upgrade sprintf stack-based overflow
8.0
CVSS
0.4%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack vector
Adjacent
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 31% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
SI
SIP-T46U · Yealink
108.86.0.118 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-12221
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-12221
cdn2.v50to.cc
http://cdn2.v50to.cc/T46U/T46U_mod_upgrade_Upgrade_chunk_stack_overflow.zip
vuldb.com
https://vuldb.com/cve/CVE-2026-12221
vuldb.com
https://vuldb.com/submit/834207
vuldb.com
https://vuldb.com/vuln/370864
vuldb.com
https://vuldb.com/vuln/370864/cti
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