How severe is CVE-2020-12638?

CVE-2020-12638 has a CVSS 3.x base score of 6.8, rated medium severity. It is exploitable over an adjacent network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2020-12638 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (37th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-12638?

CVE-2020-12638 primarily affects Espressif Esp-idf. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-12638?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2020-12638 published?

CVE-2020-12638 was published on 2020-07-23 and last updated on 2026-06-17.

CVE-2020-12638

CVE-2020-12638 is a medium-severity vulnerability in Espressif Esp-idf with a CVSS 3.x base score of 6.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-287.

Key facts

Severity: Medium (CVSS 3.x base score 6.8)
CVSS v2: 4.3
EPSS exploit prediction: 0% (37th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-287
Affected product: Espressif Esp-idf
Published: 2020-07-23
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2020-12638?: 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.
How severe is CVE-2020-12638?: CVE-2020-12638 has a CVSS 3.x base score of 6.8, rated medium severity. It is exploitable over an adjacent network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2020-12638 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (37th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-12638?: CVE-2020-12638 primarily affects Espressif Esp-idf. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-12638?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-12638 published?: CVE-2020-12638 was published on 2020-07-23 and last updated on 2026-06-17.

References

Affected products (3)

cpe:2.3:a:espressif:esp-idf:*:*:*:*:*:*:*:*
cpe:2.3:a:espressif:esp8266_nonos_sdk:*:*:*:*:*:*:*:*
cpe:2.3:a:espressif:esp8266_rtos_sdk:*:*:*:*:*:*:*:*

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