CVE-2017-20206 (GCVE-0-2017-20206)

Vulnerability from cvelistv5 – Published: 2025-10-18 03:33 – Updated: 2026-04-08 17:03
VLAI Previdian
Title
Appointments <= 2.2.1 - Unauthenticated PHP Object Injection
Summary
The Appointments plugin for WordPress is vulnerable to PHP Object Injection in versions up to, and including, 2.2.1 via deserialization of untrusted input from the `wpmudev_appointments` cookie. This allows unauthenticated attackers to inject a PHP Object. Attackers were actively exploiting this vulnerability with the WP_Theme() class to create backdoors.
Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
SSVC
Exploitation: none Automatable: yes Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2025-10-20 16:32 UTC
CWE
  • CWE-502 - Deserialization of Untrusted Data
Assigner
References
Impacted products
Vendor Product Version CPE status
wpmudev Appointments Affected: 0 , < 2.2.2 (semver)
guessed Create a notification for this product.
Credits
Matt Barry
Previdian
Known Exploited Vulnerability - GCVE BCP-07 Compliant
KEV entry ID: 6ed71c4b-f3a5-4921-94ba-52aba2b088a6

Vulnerability ID: CVE-2017-20206

Status: Confirmed

Status Updated: 2026-06-01 10:42 UTC

Exploited: Yes

Timestamps
First Seen: 2026-06-01
Asserted: 2026-06-01
Scope
Notes: KEVIntel entry: Appointments <= 2.2.1 - Unauthenticated PHP Object Injection | Affected: wpmudev / Appointments | CVSS: 9.8 (CRITICAL) | EPSS: 0.0067 | Used in malware: unknown | Not yet in CISA KEV: True
Evidence

Type: Public Report

Signal: Successful Exploitation

Confidence: 70%

Source: kevintel

Details
Feed KEVIntel (kevintel.com)
Title Appointments <= 2.2.1 - Unauthenticated PHP Object Injection
Vendor wpmudev
Product Appointments
Added Date 2026-06-01T10:42:26.109Z
Cvss Score 9.8
Epss Score 0.0067
Cvss Severity CRITICAL
Epss Percentile 0.47115
Used In Malware unknown
Ahead Of Cisa Kev None
Not Yet In Cisa Kev True
References
Created: 2026-06-19 12:42 UTC | Updated: 2026-06-19 12:42 UTC
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2017-20206",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2025-10-20T16:32:47.757313Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2025-10-20T16:32:56.505Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Appointments",
          "vendor": "wpmudev",
          "versions": [
            {
              "lessThan": "2.2.2",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Matt Barry"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "The Appointments plugin for WordPress is vulnerable to PHP Object Injection in versions up to, and including, 2.2.1 via deserialization of untrusted input from the `wpmudev_appointments` cookie. This allows unauthenticated attackers to inject a PHP Object. Attackers were actively exploiting this vulnerability with the WP_Theme() class to create backdoors."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.8,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-502",
              "description": "CWE-502 Deserialization of Untrusted Data",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-04-08T17:03:10.542Z",
        "orgId": "b15e7b5b-3da4-40ae-a43c-f7aa60e62599",
        "shortName": "Wordfence"
      },
      "references": [
        {
          "url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/7e8f230e-3f96-4efd-806d-72725b960303?source=cve"
        },
        {
          "url": "https://www.wordfence.com/blog/2017/10/3-zero-day-plugin-vulnerabilities-exploited-wild/"
        },
        {
          "url": "https://plugins.trac.wordpress.org/changeset/1733186/appointments"
        }
      ],
      "timeline": [
        {
          "lang": "en",
          "time": "2017-10-02T00:00:00.000Z",
          "value": "Disclosed"
        }
      ],
      "title": "Appointments \u003c= 2.2.1 - Unauthenticated PHP Object Injection"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "b15e7b5b-3da4-40ae-a43c-f7aa60e62599",
    "assignerShortName": "Wordfence",
    "cveId": "CVE-2017-20206",
    "datePublished": "2025-10-18T03:33:24.194Z",
    "dateReserved": "2025-10-17T15:00:24.290Z",
    "dateUpdated": "2026-04-08T17:03:10.542Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2017-20206",
      "date": "2026-10-01",
      "epss": "0.00735",
      "percentile": "0.52728"
    },
    "nvd": {
      "cve": {
        "configurations": [
          {
            "nodes": [
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:a:wpmudev:appointments:*:*:*:*:*:wordpress:*:*",
                    "matchCriteriaId": "272E0BE3-D34B-439D-9993-BBB19DBD1B0D",
                    "versionEndIncluding": "2.2.1",
                    "vulnerable": true
                  }
                ],
                "negate": false,
                "operator": "OR"
              }
            ]
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "The Appointments plugin for WordPress is vulnerable to PHP Object Injection in versions up to, and including, 2.2.1 via deserialization of untrusted input from the `wpmudev_appointments` cookie. This allows unauthenticated attackers to inject a PHP Object. Attackers were actively exploiting this vulnerability with the WP_Theme() class to create backdoors."
          }
        ],
        "id": "CVE-2017-20206",
        "lastModified": "2025-12-23T17:06:57.133",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "HIGH",
                "baseScore": 9.8,
                "baseSeverity": "CRITICAL",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 3.9,
              "impactScore": 5.9,
              "source": "security@wordfence.com",
              "type": "Secondary"
            }
          ]
        },
        "published": "2025-10-18T04:15:43.243",
        "references": [
          {
            "source": "security@wordfence.com",
            "tags": [
              "Patch"
            ],
            "url": "https://plugins.trac.wordpress.org/changeset/1733186/appointments"
          },
          {
            "source": "security@wordfence.com",
            "tags": [
              "Press/Media Coverage",
              "Third Party Advisory"
            ],
            "url": "https://www.wordfence.com/blog/2017/10/3-zero-day-plugin-vulnerabilities-exploited-wild/"
          },
          {
            "source": "security@wordfence.com",
            "tags": [
              "Third Party Advisory"
            ],
            "url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/7e8f230e-3f96-4efd-806d-72725b960303?source=cve"
          }
        ],
        "sourceIdentifier": "security@wordfence.com",
        "vulnStatus": "Analyzed",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-502"
              }
            ],
            "source": "security@wordfence.com",
            "type": "Secondary"
          }
        ]
      }
    },
    "vulnrichment": {
      "containers": {
        "adp": [
          {
            "metrics": [
              {
                "other": {
                  "content": {
                    "id": "CVE-2017-20206",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "yes"
                      },
                      {
                        "Technical Impact": "total"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2025-10-20T16:32:47.757313Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2025-10-20T16:32:51.560Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "defaultStatus": "unaffected",
              "product": "Appointments",
              "vendor": "wpmudev",
              "versions": [
                {
                  "lessThan": "2.2.2",
                  "status": "affected",
                  "version": "0",
                  "versionType": "semver"
                }
              ]
            }
          ],
          "credits": [
            {
              "lang": "en",
              "type": "finder",
              "value": "Matt Barry"
            }
          ],
          "descriptions": [
            {
              "lang": "en",
              "value": "The Appointments plugin for WordPress is vulnerable to PHP Object Injection in versions up to, and including, 2.2.1 via deserialization of untrusted input from the `wpmudev_appointments` cookie. This allows unauthenticated attackers to inject a PHP Object. Attackers were actively exploiting this vulnerability with the WP_Theme() class to create backdoors."
            }
          ],
          "metrics": [
            {
              "cvssV3_1": {
                "baseScore": 9.8,
                "baseSeverity": "CRITICAL",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
              }
            }
          ],
          "problemTypes": [
            {
              "descriptions": [
                {
                  "cweId": "CWE-502",
                  "description": "CWE-502 Deserialization of Untrusted Data",
                  "lang": "en",
                  "type": "CWE"
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2026-04-08T17:03:10.542Z",
            "orgId": "b15e7b5b-3da4-40ae-a43c-f7aa60e62599",
            "shortName": "Wordfence"
          },
          "references": [
            {
              "url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/7e8f230e-3f96-4efd-806d-72725b960303?source=cve"
            },
            {
              "url": "https://www.wordfence.com/blog/2017/10/3-zero-day-plugin-vulnerabilities-exploited-wild/"
            },
            {
              "url": "https://plugins.trac.wordpress.org/changeset/1733186/appointments"
            }
          ],
          "timeline": [
            {
              "lang": "en",
              "time": "2017-10-02T00:00:00.000Z",
              "value": "Disclosed"
            }
          ],
          "title": "Appointments \u003c= 2.2.1 - Unauthenticated PHP Object Injection"
        }
      },
      "cveMetadata": {
        "assignerOrgId": "b15e7b5b-3da4-40ae-a43c-f7aa60e62599",
        "assignerShortName": "Wordfence",
        "cveId": "CVE-2017-20206",
        "datePublished": "2025-10-18T03:33:24.194Z",
        "dateReserved": "2025-10-17T15:00:24.290Z",
        "dateUpdated": "2026-04-08T17:03:10.542Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.