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Fencer Intel
medium 6.8

CVE-2025-27840 json

Espressif ESP32 chips allow 29 hidden HCI commands, such as 0xFC02 (Write memory).

published last yr. modified 4mo ago also EUVD-2025-7816

cvss
6.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.4%
EPSS 1.4% chance of exploitation in 30 days, percentile 71%
public exploits
0
none known

Summary

Espressif ESP32 chips allow 29 hidden HCI commands, such as 0xFC02 (Write memory).

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CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
last yr.

Exploit prediction

1.36% chance of exploitation in the next 30 days, higher than 71% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • bleepingcomputer.com https://www.bleepingcomputer.com/news/security/undocumented-backdoor-found-in-bluetooth-chip-used-by-a-billion-devices/ referenced PoC, tagged "exploit" by a source, unverified
  • bleepingcomputer.com https://www.bleepingcomputer.com/news/security/undocumented-commands-found-in-bluetooth-chip-used-by-a-billion-devices/ referenced PoC, tagged "exploit" by a source, unverified
  • darkmentor.com https://darkmentor.com/blog/esp32_non-backdoor/ referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 6.8 CVSS:3.1/AV:P/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:L
NVD 3.1 6.8 CVSS:3.1/AV:P/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N

Affected products

  • Espressif ESP32

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.