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CVE-2021-28136

22
FAUCET Score

CVE-2021-28136 is a medium-severity vulnerability affecting Espressif ESP-IDF 4.4 and earlier, specifically impacting ESP32 devices. It allows an attacker within radio range to trigger memory corruption and device crashes during Bluetooth Classic pairing by replaying duplicated LMP IO Capability Request packets. The CVSS score of 6.5 indicates a network-adjacent attack with low complexity and high availability impact, but no confidentiality or integrity impact. There is no known active exploitation, public exploit code, or Metasploit modules, though it has received some community discussion and media coverage as part of the broader "BrakTooth" vulnerabilities.

Impacted Technologies

VendorProductVersion(s)CPE
<= 4.4CPE matchmatch criteria
cpe:2.3:a:espressif:esp-idf:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

6.5MEDIUM

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

Attack Vector
ADJACENT_NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
2.8
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.87%
Probability of exploitation in next 30 days
EPSS Percentile
55.1%
Percentile rank of EPSS score among Peer Group
As of 2026-07-25
Model: v2026.06.15
This CVE's current EPSS score of 0.0087 is in the 85th percentile among its peer group of 1,802 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Remediation records are not available for this CVE.

References

dl.packetstormsecurity.net / papers/general/braktooth.pdf
Technical DescriptionThird Party Advisory
github.com / espressif/esp32-bt-lib
ProductThird Party Advisory
github.com / espressif/esp-idf
ProductThird Party Advisory
espressif.com / en/products/socs/esp32
ProductVendor Advisory