Espressif ESP32 chips allow 29 hidden HCI commands, such as 0xFC02 (Write memory).
Weakness
The product contains functionality that is not documented, not part of the specification, and not accessible through an interface or command sequence that is obvious to the product’s users or administrators.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Esp32_firmware | Espressif | - (including) | - (including) |
Potential Mitigations
Related Attack Patterns
References
- https://cheriot.org/auditing/backdoor/2025/03/09/no-esp32-style-backdoor.html
- https://darkmentor.com/blog/esp32_non-backdoor/
- https://flyingpenguin.com/?p=67838
- https://github.com/TarlogicSecurity/Talks/blob/main/2025_RootedCon_BluetoothTools.pdf
- https://github.com/em0gi/CVE-2025-27840
- https://github.com/esphome/esphome/discussions/8382
- https://github.com/orgs/espruino/discussions/7699
- https://news.ycombinator.com/item?id=43301369
- https://news.ycombinator.com/item?id=43308740
- https://reg.rootedcon.com/cfp/schedule/talk/5
- https://www.bleepingcomputer.com/news/security/undocumented-backdoor-found-in-bluetooth-chip-used-by-a-billion-devices/
- https://www.bleepingcomputer.com/news/security/undocumented-commands-found-in-bluetooth-chip-used-by-a-billion-devices/
- https://www.espressif.com/en/news/Response_ESP32_Bluetooth
- https://www.tarlogic.com/news/backdoor-esp32-chip-infect-ot-devices/
- https://x.com/pascal_gujer/status/1898442439704158276