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Fencer Vulns
medium 6.8

CVE-2025-27840 json

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

published 2025-03-08 20 mo ago modified 2026-06-17 4 mo 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).

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
20 mo ago

Exploit prediction

1.36% chance of exploitation in the next 30 days, higher than 71% of all scored CVEs (FIRST EPSS, 2026-11-08).

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 Vulns 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.