CVE-2020-12638 json
An encryption-bypass issue was discovered on Espressif ESP-IDF devices through 4.2, ESP8266_NONOS_SDK devices through 3.0.3, and ESP8266_RT…
published 2020-07-23 6 y ago modified 2026-06-17 4 mo ago also EUVD-2020-4939
- cvss
- 6.8
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.4%
- EPSS 0.4% chance of exploitation in 30 days, percentile 39%
- public exploits
- 0
- none known
Summary
An encryption-bypass issue was discovered on Espressif ESP-IDF devices through 4.2, ESP8266_NONOS_SDK devices through 3.0.3, and ESP8266_RTOS_SDK devices through 3.3. Broadcasting forged beacon frames forces a device to change its authentication mode to OPEN, effectively disabling its 802.11 encryption.
Patch / fix
Exploit prediction
0.45% chance of exploitation in the next 30 days, higher than 39% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- lbsfilm.at https://lbsfilm.at/blog/wpa2-authenticationmode-downgrade-in-espressif-microprocessors referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.1 | 6.8 | CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N |
| NVD | 2.0 | 4.3 | AV:A/AC:M/Au:N/C:P/I:P/A:N |
Classification
References
-
lbsfilm.at
/blog/wpa2-authenticationmode-downgrade-in-espressif-microprocessors
exploit, patch, third-party-advisory
-
github.com
/espressif/esp-idf
third-party-advisory
-
github.com
/espressif/ESP8266_NONOS_SDK
third-party-advisory
-
github.com
/espressif/ESP8266_RTOS_SDK
third-party-advisory
Sources
- CVE List CVE-2020-12638
- NVD CVE-2020-12638
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