CVE-2026-1858 (GCVE-0-2026-1858)

Vulnerability from cvelistv5 – Published: 2026-04-29 20:15 – Updated: 2026-04-30 15:22
VLAI
Title
wget2 Improper Certificate Validation
Summary
wget2 accepts a server certificate with incorrect Key Usage (KU) or Extended Key Usage (EKU). If the attackers compromise a certificate (with the associated private key) issued for a different purpose, they may be able to reuse it for TLS server authentication.
Severity
4.8 (Medium)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-04-30 13:16 UTC
CWE
  • CWE-20 - Improper input validation
Assigner
tenable CNA under the mitre root
CNA scorecard C 71/100 over 52 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
gnu wget2 Affected: 0 , ≤ 2.2.1 (semver)
guessed Create a notification for this product.
Credits
Ireneusz Pastusiak with Tenable
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-1858",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-04-30T13:16:18.594329Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-04-30T15:22:05.205Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "wget2",
          "vendor": "gnu",
          "versions": [
            {
              "lessThanOrEqual": "2.2.1",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Ireneusz Pastusiak with Tenable"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "wget2 accepts a server certificate with incorrect Key Usage (KU) or Extended Key Usage (EKU). If the attackers compromise a certificate (with the associated private key) issued for a different purpose, they may be able to reuse it for TLS server authentication."
            }
          ],
          "value": "wget2 accepts a server certificate with incorrect Key Usage (KU) or Extended Key Usage (EKU). If the attackers compromise a certificate (with the associated private key) issued for a different purpose, they may be able to reuse it for TLS server authentication."
        }
      ],
      "impacts": [
        {
          "capecId": "CAPEC-21",
          "descriptions": [
            {
              "lang": "en",
              "value": "CAPEC-21 Exploitation of Trusted Identifiers"
            }
          ]
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 4.8,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "LOW",
            "integrityImpact": "LOW",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N",
            "version": "3.1"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-20",
              "description": "CWE-20 Improper input validation",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-04-29T20:15:50.866Z",
        "orgId": "5ac1ecc2-367a-4d16-a0b2-35d495ddd0be",
        "shortName": "tenable"
      },
      "references": [
        {
          "url": "https://www.tenable.com/security/research/tra-2026-37"
        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "title": "wget2 Improper Certificate Validation",
      "x_generator": {
        "engine": "Vulnogram 1.0.1"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "5ac1ecc2-367a-4d16-a0b2-35d495ddd0be",
    "assignerShortName": "tenable",
    "cveId": "CVE-2026-1858",
    "datePublished": "2026-04-29T20:15:50.866Z",
    "dateReserved": "2026-02-03T20:13:53.718Z",
    "dateUpdated": "2026-04-30T15:22:05.205Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-1858",
      "date": "2026-10-25",
      "epss": "0.00155",
      "percentile": "0.04628"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "wget2",
                "vendor": "gnu",
                "versions": [
                  {
                    "lessThanOrEqual": "2.2.1",
                    "status": "affected",
                    "version": "0",
                    "versionType": "semver"
                  }
                ]
              }
            ],
            "source": "vulnreport@tenable.com"
          }
        ],
        "configurations": [
          {
            "nodes": [
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:a:gnu:wget2:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "7059A7C4-12BD-4BA5-B6A7-642161B8DDA2",
                    "versionEndIncluding": "2.2.1",
                    "vulnerable": true
                  }
                ],
                "negate": false,
                "operator": "OR"
              }
            ]
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "wget2 accepts a server certificate with incorrect Key Usage (KU) or Extended Key Usage (EKU). If the attackers compromise a certificate (with the associated private key) issued for a different purpose, they may be able to reuse it for TLS server authentication."
          }
        ],
        "id": "CVE-2026-1858",
        "lastModified": "2026-06-17T10:16:37.497",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "HIGH",
                "attackVector": "NETWORK",
                "availabilityImpact": "NONE",
                "baseScore": 4.8,
                "baseSeverity": "MEDIUM",
                "confidentialityImpact": "LOW",
                "integrityImpact": "LOW",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N",
                "version": "3.1"
              },
              "exploitabilityScore": 2.2,
              "impactScore": 2.5,
              "source": "vulnreport@tenable.com",
              "type": "Secondary"
            }
          ],
          "ssvcV203": [
            {
              "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "ssvcData": {
                "id": "CVE-2026-1858",
                "options": [
                  {
                    "exploitation": "none"
                  },
                  {
                    "automatable": "no"
                  },
                  {
                    "technicalImpact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-04-30T13:16:18.594329Z",
                "version": "2.0.3"
              }
            }
          ]
        },
        "published": "2026-04-29T21:16:20.513",
        "references": [
          {
            "source": "vulnreport@tenable.com",
            "tags": [
              "Exploit",
              "Third Party Advisory"
            ],
            "url": "https://www.tenable.com/security/research/tra-2026-37"
          }
        ],
        "sourceIdentifier": "vulnreport@tenable.com",
        "vulnStatus": "Analyzed",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-20"
              }
            ],
            "source": "vulnreport@tenable.com",
            "type": "Secondary"
          }
        ]
      }
    },
    "redhat_vex": {
      "current_release_date": "2026-04-30T16:03:15+00:00",
      "cve": "CVE-2026-1858",
      "id": "CVE-2026-1858",
      "initial_release_date": "2026-04-29T20:15:50.866000+00:00",
      "product_status:known_not_affected": "1",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "wget2: wget2: Improper certificate validation allows server impersonation",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-1858.json",
      "version": "3"
    },
    "vulnrichment": {
      "containers": {
        "adp": [
          {
            "metrics": [
              {
                "other": {
                  "content": {
                    "id": "CVE-2026-1858",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "no"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2026-04-30T13:16:18.594329Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2026-04-30T13:17:35.751Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "defaultStatus": "unaffected",
              "product": "wget2",
              "vendor": "gnu",
              "versions": [
                {
                  "lessThanOrEqual": "2.2.1",
                  "status": "affected",
                  "version": "0",
                  "versionType": "semver"
                }
              ]
            }
          ],
          "credits": [
            {
              "lang": "en",
              "type": "finder",
              "value": "Ireneusz Pastusiak with Tenable"
            }
          ],
          "descriptions": [
            {
              "lang": "en",
              "supportingMedia": [
                {
                  "base64": false,
                  "type": "text/html",
                  "value": "wget2 accepts a server certificate with incorrect Key Usage (KU) or Extended Key Usage (EKU). If the attackers compromise a certificate (with the associated private key) issued for a different purpose, they may be able to reuse it for TLS server authentication."
                }
              ],
              "value": "wget2 accepts a server certificate with incorrect Key Usage (KU) or Extended Key Usage (EKU). If the attackers compromise a certificate (with the associated private key) issued for a different purpose, they may be able to reuse it for TLS server authentication."
            }
          ],
          "impacts": [
            {
              "capecId": "CAPEC-21",
              "descriptions": [
                {
                  "lang": "en",
                  "value": "CAPEC-21 Exploitation of Trusted Identifiers"
                }
              ]
            }
          ],
          "metrics": [
            {
              "cvssV3_1": {
                "attackComplexity": "HIGH",
                "attackVector": "NETWORK",
                "availabilityImpact": "NONE",
                "baseScore": 4.8,
                "baseSeverity": "MEDIUM",
                "confidentialityImpact": "LOW",
                "integrityImpact": "LOW",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N",
                "version": "3.1"
              },
              "format": "CVSS",
              "scenarios": [
                {
                  "lang": "en",
                  "value": "GENERAL"
                }
              ]
            }
          ],
          "problemTypes": [
            {
              "descriptions": [
                {
                  "cweId": "CWE-20",
                  "description": "CWE-20 Improper input validation",
                  "lang": "en",
                  "type": "CWE"
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2026-04-29T20:15:50.866Z",
            "orgId": "5ac1ecc2-367a-4d16-a0b2-35d495ddd0be",
            "shortName": "tenable"
          },
          "references": [
            {
              "url": "https://www.tenable.com/security/research/tra-2026-37"
            }
          ],
          "source": {
            "discovery": "UNKNOWN"
          },
          "title": "wget2 Improper Certificate Validation",
          "x_generator": {
            "engine": "Vulnogram 1.0.1"
          }
        }
      },
      "cveMetadata": {
        "assignerOrgId": "5ac1ecc2-367a-4d16-a0b2-35d495ddd0be",
        "assignerShortName": "tenable",
        "cveId": "CVE-2026-1858",
        "datePublished": "2026-04-29T20:15:50.866Z",
        "dateReserved": "2026-02-03T20:13:53.718Z",
        "dateUpdated": "2026-04-30T15:22:05.205Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.

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.
Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

JSON

Loading timeline…




    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.