CVE-2026-12218 Yealink SIP-T46U Web FastCGI Service beforewifitest StartReportInformation stack-based overflow
A stack-based buffer overflow in the Web FastCGI service allows local network attackers to execute arbitrary code on Yealink SIP-T46U phones.
- 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-2026-12218?
CVE-2026-12218 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 was detected in Yealink SIP-T46U 108.87.50.1. The affected element is the function StartReportInformation of the file /api/inner/beforewifitest of the component Web FastCGI Service. The manipulation of the argument port results in stack-based buffer overflow. Access to the local network is required for this attack. The exploit is now 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-2026-12218?
How do I fix CVE-2026-12218?
No fix has been published for CVE-2026-12218 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-2026-12218 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-12218 exists.
Sources
Also known as GHSA-4hcr-4qf7-mjh5.