CVE-2026-12221 — HIGH (8.0)

Vulnerability 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 Score

8.0

HIGH

CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Attack Vector

ADJACENT_NETWORK

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality

HIGH

Integrity

HIGH

Availability

HIGH

Related Weaknesses (CWE)

CWE-121 CWE-119

References

FAQ

What is CVE-2026-12221?

CVE-2026-12221 is a vulnerability with a CVSS score of 8.0 (HIGH). 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...

How severe is CVE-2026-12221?

CVE-2026-12221 has been rated HIGH with a CVSS base score of 8.0/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-12221?

Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.