CVE-2021-28136

6.5 MEDIUM 0.8% exploit odds Fix listed

What it is

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.

At a glance

Exploitability: Can be exploited from the same network segment without logging in. High risk of service disruption.
Exploit odds: 0.8% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2021-09-07 06:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-06-17 03:45 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.8% in the next 30 days (EPSS).
Severity: 6.5 MEDIUM (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2021-09-07 06:15 UTC
Last modified: 2026-06-17 03:45 UTC
Exploit probability: 0.8% · EPSS, next 30 days
Weakness: CWE-787 · Out-of-bounds write
Record status: Modified

Affected

Espressif esp-idf ≤ 4.4

Attack profile CVSS 3.1 · 6.5

Attack vector: Adjacent network
Complexity: Low
Privileges needed: None
User interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Raw vector

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

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2021-28136.md and follow it. Check whether this project is affected by CVE-2021-28136. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record