CVE-2021-28135

Name: CVE-2021-28135
Creator: NVD / NIST
Published: 2021-09-07T06:15:07.23+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.5/10EPSS 0.79%

Last modified Jun 17, 2026

CVE-2021-28135 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. The Bluetooth Classic implementation in Espressif ESP-IDF 4.4 and earlier does not properly handle the reception of continuous unsolicited LMP responses, allowing attackers in radio range to trigger a denial of service (crash) in ESP32 by flooding the target device with LMP Feature Response data.. EPSS estimates a 0.79% chance of exploitation in the next 30 days.

Description

The Bluetooth Classic implementation in Espressif ESP-IDF 4.4 and earlier does not properly handle the reception of continuous unsolicited LMP responses, allowing attackers in radio range to trigger a denial of service (crash) in ESP32 by flooding the target device with LMP Feature Response data.

Metrics

CVSS 3.1

6.5/10

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

0.79%

51.7th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Vendor	Product	Versions
Espressif	Esp-Idf	<= 4.4

References

https://dl.packetstormsecurity.net/papers/general/braktooth.pdfBroken Link
https://github.com/espressif/esp-idfThird Party Advisory
https://github.com/espressif/esp32-bt-libThird Party Advisory
https://www.espressif.com/en/products/socs/esp32Product
https://dl.packetstormsecurity.net/papers/general/braktooth.pdfBroken Link
https://github.com/espressif/esp-idfThird Party Advisory
https://github.com/espressif/esp32-bt-libThird Party Advisory
https://www.espressif.com/en/products/socs/esp32Product

Timeline

Published: Sep 7, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-28135?

How severe is CVE-2021-28135?

CVE-2021-28135 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 0.79% probability of exploitation in the next 30 days.

How do I fix CVE-2021-28135?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-28135?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST