CVE-2025-27840

Exp

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

Published: 2025-03-08 Last update: 2025-03-12 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2025-27840 is rated High Exploit Risk (65.9/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 1.26%). 3 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2025-27840

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗
— nvd_ref exploit_tag Exploit-DB ↗
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2025-27840

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.56% 1.26% +0.69%
2 2026-04-17 0.48% 0.56% +0.09%
3 2026-04-16 — 0.48% —

Full EPSS history (27 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-27840

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.8 3.1 MEDIUM
CVSS:3.1/AV:P/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:L Click to expand
Attack vector (AV:P)
Hands-on access—USB, keyboard, opening the case—not something you do purely over the wire.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:H)
They need powerful rights—admin, root, or similar—before this pays off.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 0.3 6.0 [email protected]
6.8 3.1 MEDIUM
CVSS:3.1/AV:P/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N Click to expand
Attack vector (AV:P)
Hands-on access—USB, keyboard, opening the case—not something you do purely over the wire.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:H)
They need powerful rights—admin, root, or similar—before this pays off.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 0.5 5.8 [email protected]

Weakness enumeration for CVE-2025-27840

Affected software / configurations for CVE-2025-27840

Vendor Product Version Raw CPE
espressif esp32_firmware — cpe:2.3:o:espressif:esp32_firmware:-:*:*:*:*:*:*:*

References for CVE-2025-27840

URL Tags
https://cheriot.org/auditing/backdoor/2025/03/09/no-esp32-style-backdoor.html Technical Description Third Party Advisory
https://darkmentor.com/blog/esp32_non-backdoor/ Exploit Technical Description Third Party Advisory
https://flyingpenguin.com/?p=67838 Technical Description Third Party Advisory
https://github.com/TarlogicSecurity/Talks/blob/main/2025_RootedCon_BluetoothTools.pdf Third Party Advisory
https://github.com/em0gi/CVE-2025-27840 Product
https://github.com/esphome/esphome/discussions/8382 Issue Tracking
https://github.com/orgs/espruino/discussions/7699 Issue Tracking
https://news.ycombinator.com/item?id=43301369 Issue Tracking
https://news.ycombinator.com/item?id=43308740 Issue Tracking
https://reg.rootedcon.com/cfp/schedule/talk/5 Third Party Advisory
https://www.bleepingcomputer.com/news/security/undocumented-backdoor-found-in-bluetooth-chip-used-by-a-billion-devices/ Exploit Press/Media Coverage
https://www.bleepingcomputer.com/news/security/undocumented-commands-found-in-bluetooth-chip-used-by-a-billion-devices/ Exploit Press/Media Coverage
https://www.espressif.com/en/news/Response_ESP32_Bluetooth Press/Media Coverage
https://www.tarlogic.com/news/backdoor-esp32-chip-infect-ot-devices/ Third Party Advisory
https://x.com/pascal_gujer/status/1898442439704158276 Third Party Advisory
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