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

CVE-2025-6442 (GCVE-0-2025-6442)

Vulnerability from cvelistv5 – Published: 2025-06-25 16:52 – Updated: 2025-06-25 20:42
VLAI
Title
Ruby WEBrick read_header HTTP Request Smuggling Vulnerability
Summary
Ruby WEBrick read_header HTTP Request Smuggling Vulnerability. This vulnerability allows remote attackers to smuggle arbitrary HTTP requests on affected installations of Ruby WEBrick. This issue is exploitable when the product is deployed behind an HTTP proxy that fulfills specific conditions. The specific flaw exists within the read_headers method. The issue results from the inconsistent parsing of terminators of HTTP headers. An attacker can leverage this vulnerability to smuggle arbitrary HTTP requests. Was ZDI-CAN-21876.
Severity
6.5 (Medium)
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2025-06-25 20:41 UTC
CWE
  • CWE-444 - Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
Assigner
References
Impacted products
Vendor Product Version CPE status
Ruby WEBrick Affected: 1.8.1
guessed Create a notification for this product.
Date Public
2025-06-23 14:00
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2025-6442",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2025-06-25T20:41:55.809442Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2025-06-25T20:42:41.093Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unknown",
          "product": "WEBrick",
          "vendor": "Ruby",
          "versions": [
            {
              "status": "affected",
              "version": "1.8.1"
            }
          ]
        }
      ],
      "dateAssigned": "2025-06-20T17:14:36.683Z",
      "datePublic": "2025-06-23T14:00:39.708Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "Ruby WEBrick read_header HTTP Request Smuggling Vulnerability. This vulnerability allows remote attackers to smuggle arbitrary HTTP requests on affected installations of Ruby WEBrick. This issue is exploitable when the product is deployed behind an HTTP proxy that fulfills specific conditions.\n\nThe specific flaw exists within the read_headers method. The issue results from the inconsistent parsing of terminators of HTTP headers. An attacker can leverage this vulnerability to smuggle arbitrary HTTP requests. Was ZDI-CAN-21876."
        }
      ],
      "metrics": [
        {
          "cvssV3_0": {
            "baseScore": 6.5,
            "baseSeverity": "MEDIUM",
            "vectorString": "CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N",
            "version": "3.0"
          },
          "format": "CVSS"
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-444",
              "description": "CWE-444: Inconsistent Interpretation of HTTP Requests (\u0027HTTP Request/Response Smuggling\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-06-25T16:52:24.625Z",
        "orgId": "99f1926a-a320-47d8-bbb5-42feb611262e",
        "shortName": "zdi"
      },
      "references": [
        {
          "name": "ZDI-25-414",
          "tags": [
            "x_research-advisory"
          ],
          "url": "https://www.zerodayinitiative.com/advisories/ZDI-25-414/"
        },
        {
          "name": "vendor-provided URL",
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://github.com/ruby/webrick/commit/ee60354bcb84ec33b9245e1d1aa6e1f7e8132101#diff-ad02984d873efb089aa51551bc6b7d307a53e0ba1ac439e91d69c2e58a478864"
        }
      ],
      "source": {
        "lang": "en",
        "value": "yadhukrishnam"
      },
      "title": "Ruby WEBrick read_header HTTP Request Smuggling Vulnerability"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "99f1926a-a320-47d8-bbb5-42feb611262e",
    "assignerShortName": "zdi",
    "cveId": "CVE-2025-6442",
    "datePublished": "2025-06-25T16:52:24.625Z",
    "dateReserved": "2025-06-20T17:14:36.566Z",
    "dateUpdated": "2025-06-25T20:42:41.093Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2025-6442",
      "date": "2026-09-18",
      "epss": "0.00473",
      "percentile": "0.40024"
    },
    "microsoft_vex": {
      "current_release_date": "2026-02-18T01:12:22.000Z",
      "cve": "CVE-2025-6442",
      "id": "msrc_CVE-2025-6442",
      "initial_release_date": "2025-06-02T00:00:00.000Z",
      "product_status:fixed": "4",
      "product_status:known_affected": "4",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "Ruby WEBrick read_header HTTP Request Smuggling Vulnerability",
      "url": "https://msrc.microsoft.com/csaf/vex/2025/msrc_cve-2025-6442.json",
      "version": "3"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unknown",
                "product": "WEBrick",
                "vendor": "Ruby",
                "versions": [
                  {
                    "status": "affected",
                    "version": "1.8.1"
                  }
                ]
              }
            ],
            "source": "zdi-disclosures@trendmicro.com"
          }
        ],
        "configurations": [
          {
            "nodes": [
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:a:ruby-lang:webrick:*:*:*:*:*:ruby:*:*",
                    "matchCriteriaId": "334FEC52-418A-49FC-A5C1-0FCAD123DD60",
                    "versionEndExcluding": "1.8.2",
                    "vulnerable": true
                  }
                ],
                "negate": false,
                "operator": "OR"
              }
            ]
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "Ruby WEBrick read_header HTTP Request Smuggling Vulnerability. This vulnerability allows remote attackers to smuggle arbitrary HTTP requests on affected installations of Ruby WEBrick. This issue is exploitable when the product is deployed behind an HTTP proxy that fulfills specific conditions.\n\nThe specific flaw exists within the read_headers method. The issue results from the inconsistent parsing of terminators of HTTP headers. An attacker can leverage this vulnerability to smuggle arbitrary HTTP requests. Was ZDI-CAN-21876."
          },
          {
            "lang": "es",
            "value": "Vulnerabilidad de contrabando de solicitudes HTTP en Ruby WEBrick read_header. Esta vulnerabilidad permite a atacantes remotos contrabandear solicitudes HTTP arbitrarias en las instalaciones afectadas de Ruby WEBrick. Este problema se puede explotar cuando el producto se implementa tras un proxy HTTP que cumple condiciones espec\u00edficas. La falla espec\u00edfica se encuentra en el m\u00e9todo read_headers. El problema se debe al an\u00e1lisis inconsistente de los terminadores de las cabeceras HTTP. Un atacante puede aprovechar esta vulnerabilidad para contrabandear solicitudes HTTP arbitrarias. Anteriormente, se denomin\u00f3 ZDI-CAN-21876."
          }
        ],
        "id": "CVE-2025-6442",
        "lastModified": "2026-06-17T10:01:54.183",
        "metrics": {
          "cvssMetricV30": [
            {
              "cvssData": {
                "attackComplexity": "HIGH",
                "attackVector": "NETWORK",
                "availabilityImpact": "NONE",
                "baseScore": 6.5,
                "baseSeverity": "MEDIUM",
                "confidentialityImpact": "LOW",
                "integrityImpact": "HIGH",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N",
                "version": "3.0"
              },
              "exploitabilityScore": 2.2,
              "impactScore": 4.2,
              "source": "zdi-disclosures@trendmicro.com",
              "type": "Secondary"
            }
          ],
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "HIGH",
                "attackVector": "NETWORK",
                "availabilityImpact": "NONE",
                "baseScore": 5.9,
                "baseSeverity": "MEDIUM",
                "confidentialityImpact": "NONE",
                "integrityImpact": "HIGH",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N",
                "version": "3.1"
              },
              "exploitabilityScore": 2.2,
              "impactScore": 3.6,
              "source": "nvd@nist.gov",
              "type": "Primary"
            }
          ],
          "ssvcV203": [
            {
              "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "ssvcData": {
                "id": "CVE-2025-6442",
                "options": [
                  {
                    "exploitation": "none"
                  },
                  {
                    "automatable": "no"
                  },
                  {
                    "technicalImpact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2025-06-25T20:41:55.809442Z",
                "version": "2.0.3"
              }
            }
          ]
        },
        "published": "2025-06-25T17:15:40.117",
        "references": [
          {
            "source": "zdi-disclosures@trendmicro.com",
            "tags": [
              "Patch"
            ],
            "url": "https://github.com/ruby/webrick/commit/ee60354bcb84ec33b9245e1d1aa6e1f7e8132101#diff-ad02984d873efb089aa51551bc6b7d307a53e0ba1ac439e91d69c2e58a478864"
          },
          {
            "source": "zdi-disclosures@trendmicro.com",
            "tags": [
              "Third Party Advisory"
            ],
            "url": "https://www.zerodayinitiative.com/advisories/ZDI-25-414/"
          }
        ],
        "sourceIdentifier": "zdi-disclosures@trendmicro.com",
        "vulnStatus": "Analyzed",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-444"
              }
            ],
            "source": "zdi-disclosures@trendmicro.com",
            "type": "Secondary"
          }
        ]
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-31T11:28:45+00:00",
      "cve": "CVE-2025-6442",
      "id": "CVE-2025-6442",
      "initial_release_date": "2025-06-25T16:52:24.625000+00:00",
      "product_status:known_affected": "91",
      "product_status:known_not_affected": "120",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "webrick: Ruby WEBrick Request Smuggling Vulnerability",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-6442.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-09-03T16:37:09Z",
      "cve": "CVE-2025-6442",
      "id": "CVE-2025-6442",
      "initial_release_date": "2025-06-24T23:24:29Z",
      "product_status:known_affected": "515",
      "product_status:known_not_affected": "164",
      "product_status:recommended": "132",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2025-6442",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2025-6442.json",
      "version": "29"
    },
    "vulnrichment": {
      "containers": {
        "adp": [
          {
            "metrics": [
              {
                "other": {
                  "content": {
                    "id": "CVE-2025-6442",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "no"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2025-06-25T20:41:55.809442Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2025-06-25T20:42:37.898Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "defaultStatus": "unknown",
              "product": "WEBrick",
              "vendor": "Ruby",
              "versions": [
                {
                  "status": "affected",
                  "version": "1.8.1"
                }
              ]
            }
          ],
          "dateAssigned": "2025-06-20T17:14:36.683Z",
          "datePublic": "2025-06-23T14:00:39.708Z",
          "descriptions": [
            {
              "lang": "en",
              "value": "Ruby WEBrick read_header HTTP Request Smuggling Vulnerability. This vulnerability allows remote attackers to smuggle arbitrary HTTP requests on affected installations of Ruby WEBrick. This issue is exploitable when the product is deployed behind an HTTP proxy that fulfills specific conditions.\n\nThe specific flaw exists within the read_headers method. The issue results from the inconsistent parsing of terminators of HTTP headers. An attacker can leverage this vulnerability to smuggle arbitrary HTTP requests. Was ZDI-CAN-21876."
            }
          ],
          "metrics": [
            {
              "cvssV3_0": {
                "baseScore": 6.5,
                "baseSeverity": "MEDIUM",
                "vectorString": "CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N",
                "version": "3.0"
              },
              "format": "CVSS"
            }
          ],
          "problemTypes": [
            {
              "descriptions": [
                {
                  "cweId": "CWE-444",
                  "description": "CWE-444: Inconsistent Interpretation of HTTP Requests (\u0027HTTP Request/Response Smuggling\u0027)",
                  "lang": "en",
                  "type": "CWE"
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2025-06-25T16:52:24.625Z",
            "orgId": "99f1926a-a320-47d8-bbb5-42feb611262e",
            "shortName": "zdi"
          },
          "references": [
            {
              "name": "ZDI-25-414",
              "tags": [
                "x_research-advisory"
              ],
              "url": "https://www.zerodayinitiative.com/advisories/ZDI-25-414/"
            },
            {
              "name": "vendor-provided URL",
              "tags": [
                "vendor-advisory"
              ],
              "url": "https://github.com/ruby/webrick/commit/ee60354bcb84ec33b9245e1d1aa6e1f7e8132101#diff-ad02984d873efb089aa51551bc6b7d307a53e0ba1ac439e91d69c2e58a478864"
            }
          ],
          "source": {
            "lang": "en",
            "value": "yadhukrishnam"
          },
          "title": "Ruby WEBrick read_header HTTP Request Smuggling Vulnerability"
        }
      },
      "cveMetadata": {
        "assignerOrgId": "99f1926a-a320-47d8-bbb5-42feb611262e",
        "assignerShortName": "zdi",
        "cveId": "CVE-2025-6442",
        "datePublished": "2025-06-25T16:52:24.625Z",
        "dateReserved": "2025-06-20T17:14:36.566Z",
        "dateUpdated": "2025-06-25T20:42:41.093Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.1"
    }
  }
}



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.


Detection rules are retrieved from Rulezet.


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.