What’s Vulnerable › Vulnerabilities

CVE-2020-12638

• Severity: medium (CVSS 6.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2020-07-23 · updated 2026-06-17
• Weakness: CWE-287

Description

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.

Affected products

• espressif esp-idf: through 4.2
• espressif Esp8266 Nonos Sdk: through 3.0.3
• espressif Esp8266 Rtos Sdk: through 3.3

References

• https://github.com/espressif/ESP8266_NONOS_SDK
• https://github.com/espressif/ESP8266_RTOS_SDK
• https://github.com/espressif/esp-idf
• https://lbsfilm.at/blog/wpa2-authenticationmode-downgrade-in-espressif-microprocessors
• https://github.com/espressif/ESP8266_NONOS_SDK
• https://github.com/espressif/ESP8266_RTOS_SDK
• https://github.com/espressif/esp-idf
• https://lbsfilm.at/blog/wpa2-authenticationmode-downgrade-in-espressif-microprocessors

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