Security advisory

{
  "id": "c5591bb1bc0d509239193d87173554898b96266e86726931c60c74cb105822a8",
  "url": "https://osv.dev/vulnerability/CVE-2020-12638",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2020-12638",
    "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.",
    "evidence": "osv:CVE-2020-12638",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2020-12638",
      "aliases": [
        "CVE-2020-12638"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/espressif/esp-idf",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "last_affected": "ee899cb2aac50349bb83524910f4f34920579386"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:espressif:esp-idf:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "last_affected": "4.2"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v4.2-dev",
            "v4.1-dev",
            "v4.0-dev",
            "v3.3-beta2",
            "v3.3-beta1",
            "v3.2-beta1",
            "v3.3-dev",
            "v3.1-beta1",
            "v3.2-dev",
            "v3.1-dev",
            "v2.1-rc1",
            "v3.0-dev",
            "v2.0-rc1",
            "v1.0",
            "v0.9"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2020-12638.json"
          }
        },
        {
          "ranges": [
            {
              "repo": "https://github.com/espressif/esp8266_nonos_sdk",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "last_affected": "3fe474e040450e0ab72ea75f8f00c3d9c6279025"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:espressif:esp8266_nonos_sdk:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "last_affected": "3.0.3"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v3.0.3",
            "v3.0.2",
            "v3.0",
            "v2.2.0",
            "v2.1.0",
            "v2.0.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2020-12638.json"
          }
        },
        {
          "ranges": [
            {
              "repo": "https://github.com/espressif/esp8266_rtos_sdk",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "last_affected": "9f9ee5a97b4818b110bde88eb60c602569a0038d"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:espressif:esp8266_rtos_sdk:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "last_affected": "3.3"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v3.2",
            "v3.3-dev",
            "v3.1-rc1",
            "v3.2-dev",
            "v3.1-dev",
            "v3.0-rc1",
            "v3.0-dev",
            "v2.0.0",
            "v2.0.0-rc1",
            "v1.5.0",
            "v1.4.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2020-12638.json"
          }
        }
      ],
      "modified": "2026-10-20T10:51:47.064317959Z",
      "provider": "osv",
      "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"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2020-12638",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 382938,
  "published_at": "2020-07-23T16:15:12.49+00:00"
}