CVE-2021-28136: Espressif Esp-Idf

Medium severity, CVSS 6.5. EPSS: 0.8% chance of exploitation in the next 30 days.

The Bluetooth Classic implementation in Espressif ESP-IDF 4.4 and earlier does not properly handle the reception of multiple LMP IO Capability Request packets during the pairing process, allowing attackers in radio range to trigger memory corruption (and consequently a crash) in ESP32 via a replayed (duplicated) LMP packet.

Affected products

• Espressif Esp-Idf: up to and including 4.4

Published 2021-09-07. Last modified 2026-06-17.