PatchTheCVECVE-2025-27840: Espressif ESP32 chips allow 29 hidden HCI commands, such as 0xFC02 (Write memory).
CVE-2025-27840 is a medium-severity flaw (CVSS 6.8) affecting esp32 firmware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
Espressif ESP32 chips allow 29 hidden HCI commands, such as 0xFC02 (Write memory).
Why this priority
- Public exploit reference
No fix is published yet: follow the downgrade or mitigation steps.
Risk facts
| CVSS score | 6.8 (Medium) |
| Attack vector | Physical |
| Attack complexity | High |
| Privileges needed | High |
| User interaction | None |
| EPSS exploit chance | 1.4% (top 28%) |
| CISA exploited list | No |
| Weakness | CWE-912 |
| Published | 2025-03-08 |
| Last modified | 2026-06-17 |
Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2025-27840?
esp32 firmware: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.
Is CVE-2025-27840 being exploited?
CVE-2025-27840 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2025-27840 affect?
CVE-2025-27840 affects esp32 firmware. Severity is medium (CVSS 6.8). Espressif ESP32 chips allow 29 hidden HCI commands, such as 0xFC02 (Write memory).
How urgent is CVE-2025-27840?
Priority 47/100. Public exploit reference