The Bluetooth Classic implementation in the Zhuhai Jieli AC6366C BT SDK through 0.9.1 does not properly handle the reception of truncated LMP_SCO_Link_Request packets while no other BT connections are active, allowing attackers in radio range to prevent new BT connections (disabling the AB5301A inquiry and page scan procedures) via a crafted LMP packet. The user needs to manually perform a power cycle (restart) of the device to restore BT connectivity.
Conclusion & alert: CVE-2021-34144 is rated Moderate Risk (42.9/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.67%). Mandatory action: Review affected assets and schedule remediation.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-06-15 | 0.14% | 0.67% | +0.53% |
| 2 | 2025-03-30 | 0.20% | 0.14% | -0.06% |
| 3 | 2025-03-29 | — | 0.20% | — |
Full EPSS history (8 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 6.5 | 3.1 | MEDIUM |
|
2.8 | 3.6 | [email protected] |
| 3.3 | 2.0 | LOW |
|
6.5 | 2.9 | [email protected] |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| zh-jieli | fw-ac63_bt_sdk | <= 0.9.1 | cpe:2.3:o:zh-jieli:fw-ac63_bt_sdk:*:*:*:*:*:*:*:* |
| URL | Tags |
|---|---|
| https://dl.packetstormsecurity.net/papers/general/braktooth.pdf | Technical Description Third Party Advisory |
| https://github.com/Jieli-Tech/fw-AC63_BT_SDK | Third Party Advisory |
| https://launchstudio.bluetooth.com/ListingDetails/91371 | Third Party Advisory |