GCVE Workshop - 22 September 2026 (14:00-18:00), Luxembourg Before The Vulnopticon Conference - Registration

CVE-2021-22017 (GCVE-0-2021-22017)

Vulnerability from cvelistv5 – Published: 2021-09-23 12:13 – Updated: 2025-10-21 23:25
VLAI CISA Shadowserver Previdian
Summary
Rhttproxy as used in vCenter Server contains a vulnerability due to improper implementation of URI normalization. A malicious actor with network access to port 443 on vCenter Server may exploit this issue to bypass proxy leading to internal endpoints being accessed.
SSVC
Exploitation: active Automatable: yes Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2025-01-29 17:54 UTC
CWE
References
Impacted products
Vendor Product Version CPE status
n/a VMware vCenter Server, VMware Cloud Foundation Affected: VMware vCenter Server(6.7 before 6.7 U3o and 6.5 before 6.5 U3q) and VMware Cloud Foundation 3.x before 3.10.2.2
CISA
Known Exploited Vulnerability - GCVE BCP-07 Compliant

Vulnerability ID: CVE-2021-22017

Status: Confirmed

Status Updated: 2022-01-10 00:00 UTC

Exploited: Yes


Timestamps
First Seen: 2022-01-10
Asserted: 2022-01-10

Scope
Notes: KEV entry: VMware vCenter Server Improper Access Control | Affected: VMware / vCenter Server | Description: Rhttproxy as used in vCenter Server contains a vulnerability due to improper implementation of URI normalization. | Required action: Apply updates per vendor instructions. | Due date: 2022-01-24 | Known ransomware campaign use (KEV): Unknown | Notes (KEV): https://nvd.nist.gov/vuln/detail/CVE-2021-22017

Evidence

Type: Vendor Report

Signal: Successful Exploitation

Confidence: 80%

Source: cisa-kev


Details
Cwes CWE-23
Feed CISA Known Exploited Vulnerabilities Catalog
Product vCenter Server
Due Date 2022-01-24
Date Added 2022-01-10
Vendorproject VMware
Vulnerabilityname VMware vCenter Server Improper Access Control
Knownransomwarecampaignuse Unknown

References

Created: 2026-02-02 13:25 UTC | Updated: 2026-02-06 07:53 UTC
Shadowserver
Known Exploited Vulnerability - GCVE BCP-07 Compliant

Vulnerability ID: CVE-2021-22017

Status: Confirmed

Status Updated: 2026-09-05 00:00 UTC

Exploited: Yes


Characteristics
Severity: 53.0

Timestamps
First Seen: 2026-04-21
Asserted: 2026-04-21
Last Seen: 2026-09-05

Scope
Asset Exposure: ['internet-facing']
Notes: Affected: VMware / vCenter Server | Class: other-software | Severity: Medium (CVSS 5.3) | IoT: no | In CISA KEV: yes | Honeypot connections on 2026-09-05: 1

Evidence

Type: Honeypot

Signal: In The Wild Attempts

Confidence: 70%

Source: shadowserver


Details
1D 1
Iot no
Feed Shadowserver Foundation honeypot/exploited-vulnerabilities
Type http-scan
Class other-software
7D Avg 1
Vendor VMware
30D Avg 0
90D Avg 0
Product vCenter Server
Cisa Kev yes
Connections 1
Observation Date 2026-09-05
Vulnerability Class CVSS
Vulnerability Score 5.3
Vulnerability Severity Medium

References

Created: 2026-07-01 05:54 UTC | Updated: 2026-09-07 01:01 UTC
Previdian
Known Exploited Vulnerability - GCVE BCP-07 Compliant

Vulnerability ID: CVE-2021-22017

Status: Confirmed

Status Updated: 2022-01-10 00:00 UTC

Exploited: Yes


Timestamps
First Seen: 2022-01-10
Asserted: 2022-01-10

Scope
Notes: KEVIntel entry: Rhttproxy as used in vCenter Server contains a vulnerability due to improper implementation of URI normalization. A malicious actor with network... | Affected: VMware / VMware vCenter Server, VMware Cloud Foundation | CVSS: 5.3 (MEDIUM) | Used in malware: unknown | Not yet in CISA KEV: False

Evidence

Type: Public Report

Signal: Successful Exploitation

Confidence: 70%

Source: kevintel


Details
Feed KEVIntel (kevintel.com)
Title Rhttproxy as used in vCenter Server contains a vulnerability due to improper implementation of URI normalization. A malicious actor with network...
Vendor VMware
Product VMware vCenter Server, VMware Cloud Foundation
Added Date 2022-01-10T00:00:00.000Z
Cvss Score 5.3
Epss Score None
Cvss Severity MEDIUM
Epss Percentile None
Used In Malware unknown
Ahead Of Cisa Kev None
Not Yet In Cisa Kev False

References

Created: 2026-06-23 11:13 UTC | Updated: 2026-06-23 11:13 UTC
Show details on NVD website

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-03T18:30:23.942Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "tags": [
              "x_refsource_MISC",
              "x_transferred"
            ],
            "url": "https://www.vmware.com/security/advisories/VMSA-2021-0020.html"
          }
        ],
        "title": "CVE Program Container"
      },
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "NETWORK",
              "availabilityImpact": "NONE",
              "baseScore": 5.3,
              "baseSeverity": "MEDIUM",
              "confidentialityImpact": "LOW",
              "integrityImpact": "NONE",
              "privilegesRequired": "NONE",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2021-22017",
                "options": [
                  {
                    "Exploitation": "active"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2025-01-29T17:54:48.927818Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          },
          {
            "other": {
              "content": {
                "dateAdded": "2022-01-10",
                "reference": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-22017"
              },
              "type": "kev"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "description": "CWE-noinfo Not enough information",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2025-10-21T23:25:31.570Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "government-resource"
            ],
            "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-22017"
          }
        ],
        "timeline": [
          {
            "lang": "en",
            "time": "2022-01-10T00:00:00.000Z",
            "value": "CVE-2021-22017 added to CISA KEV"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "VMware vCenter Server, VMware Cloud Foundation",
          "vendor": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "VMware vCenter Server(6.7 before 6.7 U3o and 6.5 before 6.5 U3q) and VMware Cloud Foundation 3.x before 3.10.2.2"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Rhttproxy as used in vCenter Server contains a vulnerability due to improper implementation of URI normalization. A malicious actor with network access to port 443 on vCenter Server may exploit this issue to bypass proxy leading to internal endpoints being accessed."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "description": "Rhttpproxy bypass vulnerability",
              "lang": "en",
              "type": "text"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2021-09-23T12:13:01.000Z",
        "orgId": "dcf2e128-44bd-42ed-91e8-88f912c1401d",
        "shortName": "vmware"
      },
      "references": [
        {
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://www.vmware.com/security/advisories/VMSA-2021-0020.html"
        }
      ],
      "x_legacyV4Record": {
        "CVE_data_meta": {
          "ASSIGNER": "security@vmware.com",
          "ID": "CVE-2021-22017",
          "STATE": "PUBLIC"
        },
        "affects": {
          "vendor": {
            "vendor_data": [
              {
                "product": {
                  "product_data": [
                    {
                      "product_name": "VMware vCenter Server, VMware Cloud Foundation",
                      "version": {
                        "version_data": [
                          {
                            "version_value": "VMware vCenter Server(6.7 before 6.7 U3o and 6.5 before 6.5 U3q) and VMware Cloud Foundation 3.x before 3.10.2.2"
                          }
                        ]
                      }
                    }
                  ]
                },
                "vendor_name": "n/a"
              }
            ]
          }
        },
        "data_format": "MITRE",
        "data_type": "CVE",
        "data_version": "4.0",
        "description": {
          "description_data": [
            {
              "lang": "eng",
              "value": "Rhttproxy as used in vCenter Server contains a vulnerability due to improper implementation of URI normalization. A malicious actor with network access to port 443 on vCenter Server may exploit this issue to bypass proxy leading to internal endpoints being accessed."
            }
          ]
        },
        "problemtype": {
          "problemtype_data": [
            {
              "description": [
                {
                  "lang": "eng",
                  "value": "Rhttpproxy bypass vulnerability"
                }
              ]
            }
          ]
        },
        "references": {
          "reference_data": [
            {
              "name": "https://www.vmware.com/security/advisories/VMSA-2021-0020.html",
              "refsource": "MISC",
              "url": "https://www.vmware.com/security/advisories/VMSA-2021-0020.html"
            }
          ]
        }
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "dcf2e128-44bd-42ed-91e8-88f912c1401d",
    "assignerShortName": "vmware",
    "cveId": "CVE-2021-22017",
    "datePublished": "2021-09-23T12:13:01.000Z",
    "dateReserved": "2021-01-04T00:00:00.000Z",
    "dateUpdated": "2025-10-21T23:25:31.570Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1",
  "vulnerability-lookup:meta": {
    "cisa_known_exploited": {
      "cveID": "CVE-2021-22017",
      "cwes": [
        "CWE-23"
      ],
      "dateAdded": "2022-01-10",
      "dueDate": "2022-01-24",
      "forensicTriage": "No",
      "knownRansomwareCampaignUse": "Unknown",
      "notes": "https://nvd.nist.gov/vuln/detail/CVE-2021-22017",
      "product": "vCenter Server",
      "requiredAction": "Apply updates per vendor instructions.",
      "shortDescription": "Rhttproxy as used in vCenter Server contains a vulnerability due to improper implementation of URI normalization.",
      "vendorProject": "VMware",
      "vulnerabilityName": "VMware vCenter Server Improper Access Control"
    },
    "epss": {
      "cve": "CVE-2021-22017",
      "date": "2026-09-20",
      "epss": "0.49177",
      "percentile": "0.98829"
    },
    "nvd": {
      "cve": {
        "cisaActionDue": "2022-01-24",
        "cisaExploitAdd": "2022-01-10",
        "cisaRequiredAction": "Apply updates per vendor instructions.",
        "cisaVulnerabilityName": "VMware vCenter Server Improper Access Control",
        "configurations": [
          {
            "nodes": [
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:a:vmware:vcenter_server:6.7:-:*:*:*:*:*:*",
                    "matchCriteriaId": "E456F84C-A86E-4EA9-9A3E-BEEA662136E6",
                    "vulnerable": true
                  }
                ],
                "negate": false,
                "operator": "OR"
              }
            ]
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "Rhttproxy as used in vCenter Server contains a vulnerability due to improper implementation of URI normalization. A malicious actor with network access to port 443 on vCenter Server may exploit this issue to bypass proxy leading to internal endpoints being accessed."
          },
          {
            "lang": "es",
            "value": "Rhttproxy, tal y como se usa en vCenter Server, contiene una vulnerabilidad debido a una implementaci\u00f3n inapropiada de la normalizaci\u00f3n de URI. Un actor malicioso con acceso de red al puerto 443 en vCenter Server puede explotar este problema para omitir el proxy, conllevando a un acceso a endpoints internos"
          }
        ],
        "id": "CVE-2021-22017",
        "lastModified": "2025-10-30T20:05:09.117",
        "metrics": {
          "cvssMetricV2": [
            {
              "acInsufInfo": false,
              "baseSeverity": "MEDIUM",
              "cvssData": {
                "accessComplexity": "LOW",
                "accessVector": "NETWORK",
                "authentication": "NONE",
                "availabilityImpact": "NONE",
                "baseScore": 5.0,
                "confidentialityImpact": "PARTIAL",
                "integrityImpact": "NONE",
                "vectorString": "AV:N/AC:L/Au:N/C:P/I:N/A:N",
                "version": "2.0"
              },
              "exploitabilityScore": 10.0,
              "impactScore": 2.9,
              "obtainAllPrivilege": false,
              "obtainOtherPrivilege": false,
              "obtainUserPrivilege": false,
              "source": "nvd@nist.gov",
              "type": "Primary",
              "userInteractionRequired": false
            }
          ],
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "NONE",
                "baseScore": 5.3,
                "baseSeverity": "MEDIUM",
                "confidentialityImpact": "LOW",
                "integrityImpact": "NONE",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N",
                "version": "3.1"
              },
              "exploitabilityScore": 3.9,
              "impactScore": 1.4,
              "source": "nvd@nist.gov",
              "type": "Primary"
            },
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "NONE",
                "baseScore": 5.3,
                "baseSeverity": "MEDIUM",
                "confidentialityImpact": "LOW",
                "integrityImpact": "NONE",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N",
                "version": "3.1"
              },
              "exploitabilityScore": 3.9,
              "impactScore": 1.4,
              "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "type": "Secondary"
            }
          ]
        },
        "published": "2021-09-23T13:15:08.207",
        "references": [
          {
            "source": "security@vmware.com",
            "tags": [
              "Patch",
              "Vendor Advisory"
            ],
            "url": "https://www.vmware.com/security/advisories/VMSA-2021-0020.html"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Patch",
              "Vendor Advisory"
            ],
            "url": "https://www.vmware.com/security/advisories/VMSA-2021-0020.html"
          },
          {
            "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
            "tags": [
              "US Government Resource"
            ],
            "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-22017"
          }
        ],
        "sourceIdentifier": "security@vmware.com",
        "vulnStatus": "Analyzed",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "NVD-CWE-noinfo"
              }
            ],
            "source": "nvd@nist.gov",
            "type": "Primary"
          }
        ]
      }
    },
    "vulnrichment": {
      "containers": {
        "adp": [
          {
            "providerMetadata": {
              "dateUpdated": "2024-08-03T18:30:23.942Z",
              "orgId": "af854a3a-2127-422b-91ae-364da2661108",
              "shortName": "CVE"
            },
            "references": [
              {
                "tags": [
                  "x_refsource_MISC",
                  "x_transferred"
                ],
                "url": "https://www.vmware.com/security/advisories/VMSA-2021-0020.html"
              }
            ],
            "title": "CVE Program Container"
          },
          {
            "metrics": [
              {
                "cvssV3_1": {
                  "attackComplexity": "LOW",
                  "attackVector": "NETWORK",
                  "availabilityImpact": "NONE",
                  "baseScore": 5.3,
                  "baseSeverity": "MEDIUM",
                  "confidentialityImpact": "LOW",
                  "integrityImpact": "NONE",
                  "privilegesRequired": "NONE",
                  "scope": "UNCHANGED",
                  "userInteraction": "NONE",
                  "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N",
                  "version": "3.1"
                }
              },
              {
                "other": {
                  "content": {
                    "id": "CVE-2021-22017",
                    "options": [
                      {
                        "Exploitation": "active"
                      },
                      {
                        "Automatable": "yes"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2025-01-29T17:54:48.927818Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              },
              {
                "other": {
                  "content": {
                    "dateAdded": "2022-01-10",
                    "reference": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-22017"
                  },
                  "type": "kev"
                }
              }
            ],
            "problemTypes": [
              {
                "descriptions": [
                  {
                    "description": "CWE-noinfo Not enough information",
                    "lang": "en",
                    "type": "CWE"
                  }
                ]
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2025-01-29T17:54:37.928Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "references": [
              {
                "tags": [
                  "government-resource"
                ],
                "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-22017"
              }
            ],
            "timeline": [
              {
                "lang": "en",
                "time": "2022-01-10T00:00:00.000Z",
                "value": "CVE-2021-22017 added to CISA KEV"
              }
            ],
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "product": "VMware vCenter Server, VMware Cloud Foundation",
              "vendor": "n/a",
              "versions": [
                {
                  "status": "affected",
                  "version": "VMware vCenter Server(6.7 before 6.7 U3o and 6.5 before 6.5 U3q) and VMware Cloud Foundation 3.x before 3.10.2.2"
                }
              ]
            }
          ],
          "descriptions": [
            {
              "lang": "en",
              "value": "Rhttproxy as used in vCenter Server contains a vulnerability due to improper implementation of URI normalization. A malicious actor with network access to port 443 on vCenter Server may exploit this issue to bypass proxy leading to internal endpoints being accessed."
            }
          ],
          "problemTypes": [
            {
              "descriptions": [
                {
                  "description": "Rhttpproxy bypass vulnerability",
                  "lang": "en",
                  "type": "text"
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2021-09-23T12:13:01.000Z",
            "orgId": "dcf2e128-44bd-42ed-91e8-88f912c1401d",
            "shortName": "vmware"
          },
          "references": [
            {
              "tags": [
                "x_refsource_MISC"
              ],
              "url": "https://www.vmware.com/security/advisories/VMSA-2021-0020.html"
            }
          ],
          "x_legacyV4Record": {
            "CVE_data_meta": {
              "ASSIGNER": "security@vmware.com",
              "ID": "CVE-2021-22017",
              "STATE": "PUBLIC"
            },
            "affects": {
              "vendor": {
                "vendor_data": [
                  {
                    "product": {
                      "product_data": [
                        {
                          "product_name": "VMware vCenter Server, VMware Cloud Foundation",
                          "version": {
                            "version_data": [
                              {
                                "version_value": "VMware vCenter Server(6.7 before 6.7 U3o and 6.5 before 6.5 U3q) and VMware Cloud Foundation 3.x before 3.10.2.2"
                              }
                            ]
                          }
                        }
                      ]
                    },
                    "vendor_name": "n/a"
                  }
                ]
              }
            },
            "data_format": "MITRE",
            "data_type": "CVE",
            "data_version": "4.0",
            "description": {
              "description_data": [
                {
                  "lang": "eng",
                  "value": "Rhttproxy as used in vCenter Server contains a vulnerability due to improper implementation of URI normalization. A malicious actor with network access to port 443 on vCenter Server may exploit this issue to bypass proxy leading to internal endpoints being accessed."
                }
              ]
            },
            "problemtype": {
              "problemtype_data": [
                {
                  "description": [
                    {
                      "lang": "eng",
                      "value": "Rhttpproxy bypass vulnerability"
                    }
                  ]
                }
              ]
            },
            "references": {
              "reference_data": [
                {
                  "name": "https://www.vmware.com/security/advisories/VMSA-2021-0020.html",
                  "refsource": "MISC",
                  "url": "https://www.vmware.com/security/advisories/VMSA-2021-0020.html"
                }
              ]
            }
          }
        }
      },
      "cveMetadata": {
        "assignerOrgId": "dcf2e128-44bd-42ed-91e8-88f912c1401d",
        "assignerShortName": "vmware",
        "cveId": "CVE-2021-22017",
        "datePublished": "2021-09-23T12:13:01.000Z",
        "dateReserved": "2021-01-04T00:00:00.000Z",
        "dateUpdated": "2025-10-21T23:25:31.570Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.1"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.


Loading…

Loading…

Loading…

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.

Loading…

Detection rules are retrieved from Rulezet.

Loading…

Loading…

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.


Loading…