CVE-2026-12220 Yealink SIP-T46U Firmware Chunk Upload handler accupgradebychunk mod_upgrade.SparePartsUpload stack-based overflow
A stack-based buffer overflow in the Yealink SIP-T46U firmware allows local network attackers to execute arbitrary code via the chunk upload handler.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-12220?
CVE-2026-12220 is a high-severity memory corruption vulnerability in Yealink SIP-T46U, published on 15 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
A vulnerability has been found in Yealink SIP-T46U 108.86.0.118. This affects the function mod_upgrade.SparePartsUpload of the file /api/upgrade/accupgradebychunk of the component Firmware Chunk Upload handler. Such manipulation of the argument uid leads to stack-based buffer overflow. The attack can only be initiated within the local network. The exploit has been disclosed to the public and may be used. The vendor was contacted early about this disclosure and is working on a patch to fix it.
Which versions are affected by CVE-2026-12220?
How do I fix CVE-2026-12220?
No fix has been published for CVE-2026-12220 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-12220 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-12220 exists.
Sources
Also known as GHSA-xgmc-rwmg-ch77.