CVE-2026-12221

HIGH 8.0

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

CVSS Score

8.0

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-121 CWE-119
Vendor	yealink
Product	sip-t46u
Published	Jun 15, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:X/RC:R

Attack Vector

Attack Complexity

Privileges Required

User Interaction

Scope

Confidentiality

Integrity

Availability

Affected Versions

Yealink / SIP-T46U

108.86.0.118

References

NVD ↗ CVE.org ↗ EPSS Data ↗

vuldb.com: https://vuldb.com/vuln/370864 vuldb.com: https://vuldb.com/vuln/370864/cti vuldb.com: https://vuldb.com/cve/CVE-2026-12221 vuldb.com: https://vuldb.com/submit/834207 cdn2.v50to.cc: http://cdn2.v50to.cc/T46U/T46U_mod_upgrade_Upgrade_chunk_stack_overflow.zip

Credits

🔍 CookedMelon (VulDB User) VulDB CNA Team