CVE-2021-31611

Severity: medium (CVSS 5.7 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-09-07 · updated 2026-06-17
Weakness: CWE-667

Description

The Bluetooth Classic implementation on Zhuhai Jieli AC690X and AC692X devices does not properly handle an out-of-order LMP Setup procedure that is followed by a malformed LMP packet, allowing attackers in radio range to deadlock a device via a crafted LMP packet. The user needs to manually reboot the device to restore communication.

Affected products

Zh-Jieli Ac6901 Firmware: all versions
Zh-Jieli Ac6921 Firmware: all versions
Zh-Jieli Ac6925 Firmware: all versions
Zh-Jieli Ac6926 Firmware: all versions
Zh-Jieli Ac6928 Firmware: all versions

References

http://www.zh-jieli.com/product/68-cn.html
https://dl.packetstormsecurity.net/papers/general/braktooth.pdf
https://launchstudio.bluetooth.com/ListingDetails/19746
https://launchstudio.bluetooth.com/ListingDetails/58628
http://www.zh-jieli.com/product/68-cn.html
https://dl.packetstormsecurity.net/papers/general/braktooth.pdf
https://launchstudio.bluetooth.com/ListingDetails/19746
https://launchstudio.bluetooth.com/ListingDetails/58628

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