CVE-2020-12638 — An encryption-bypass issue was discovered on Espressif ESP-IDF devices through 4

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 disablin

01What is this vulnerability?

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.

02Affected products

Vendor	Product	Versions
n	a / n/a	n/a

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2020-07-23T15:41:58.000Z
• Last modified: 2024-08-04T12:04:22.314Z

09References

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