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CVE-2025-27840
Espressif ESP32 chips allow 29 hidden HCI commands, such as 0xFC02 (Write memory).
Medium6.8EPSS 1.4%
- Published
- Updated
- Reserved
- Assigned by
- mitre
Description
Espressif ESP32 chips allow 29 hidden HCI commands, such as 0xFC02 (Write memory).
Timeline
Published
- 2 months later
· 2 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| mitreCNA (assigner) | 3.1 | Medium6.8 | CVSS:3.1/AV:P/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:L |
| NVDNVD · Analyzed | 3.1 | Medium6.8 | CVSS:3.1/AV:P/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N |
- EPSS (exploitation in 30 days)
- 1.4% · top 28% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
Loading the EPSS history…
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.8.
Weakness
Affected products
References (15)
- https://github.com/TarlogicSecurity/Talks/blob/main/2025_RootedCon_BluetoothTools.pdf (opens in a new tab)
- https://x.com/pascal_gujer/status/1898442439704158276 (opens in a new tab)
- https://www.tarlogic.com/news/backdoor-esp32-chip-infect-ot-devices/ (opens in a new tab)
- https://www.bleepingcomputer.com/news/security/undocumented-backdoor-found-in-bluetooth-chip-used-by-a-billion-devices/ (opens in a new tab)
- https://reg.rootedcon.com/cfp/schedule/talk/5 (opens in a new tab)
- https://flyingpenguin.com/?p=67838 (opens in a new tab)
- https://github.com/em0gi/CVE-2025-27840 (opens in a new tab)
- https://github.com/orgs/espruino/discussions/7699 (opens in a new tab)
- https://www.bleepingcomputer.com/news/security/undocumented-commands-found-in-bluetooth-chip-used-by-a-billion-devices/ (opens in a new tab)
- https://darkmentor.com/blog/esp32_non-backdoor/ (opens in a new tab)
- https://news.ycombinator.com/item?id=43308740 (opens in a new tab)
- https://news.ycombinator.com/item?id=43301369 (opens in a new tab)
- https://github.com/esphome/esphome/discussions/8382 (opens in a new tab)
- https://cheriot.org/auditing/backdoor/2025/03/09/no-esp32-style-backdoor.html (opens in a new tab)
- https://www.espressif.com/en/news/Response_ESP32_Bluetooth (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2025-27840)Record last updated .