CVE-2025-27840Public exploit

Memory access via undocumented Bluetooth HCI commands

Published Mar 8, 2025 · Updated May 12, 2025

Hidden functionality in the ESP32 Bluetooth controller allows attackers to read or write chip memory through undocumented HCI commands. The controller accepts 29 vendor-specific debug opcodes, including 0xFC02, from its trusted HCI host and performs privileged RAM, flash, packet, and control operations. Reachability is limited to less-common UART-HCI deployments after compromise of the external host or physical serial access; standard Bluetooth radio and Internet traffic cannot invoke the commands directly.

CVSS severity6.8
Medium
EPSS probability1.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Hidden functionality in the ESP32 Bluetooth controller allows attackers to read or write chip memory through undocumented HCI commands. The controller accepts 29 vendor-specific debug opcodes, including 0xFC02, from its trusted HCI host and performs privileged RAM, flash, packet, and control operations. Reachability is limited to less-common UART-HCI deployments after compromise of the external host or physical serial access; standard Bluetooth radio and Internet traffic cannot invoke the commands directly.

The record

CVE
CVE-2025-27840
Published
Mar 8, 2025
Updated
May 12, 2025
Vendor
Espressif Systems
Product
ESP32
Classifications
CWE-912
Attack vector
physical
Privileges
admin

Timeline

How it unfolded

  1. Mar 8, 2025CVE publishedPublication date reported by the CVE source.
  2. May 12, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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  1. Affected versionversion=2025-03-06

What conditions does exploitation require?

Attack vectorphysical
Required privilegesadmin

What is affected?

Espressif Systems · ESP32version=2025-03-06

Published CVSS scores

6.8MITRECVSS:3.1/AV:P/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:L
6.8NVDCVSS:3.1/AV:P/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorphysical
Privilegesadmin
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-912Hidden Functionality

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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