Vulnerability-Lookup

CVE-2026-91143 (GCVE-0-2026-91143)

Vulnerability from cvelistv5 – Published: 2026-09-14 21:45 – Updated: 2026-09-14 21:45

Title

goproxy through 15.3 Authentication Bypass via CONNECT

Summary

goproxy through 15.3 fails to apply HTTP proxy basic authentication to CONNECT tunnel requests, allowing unauthenticated clients to bypass credential requirements. Attackers can issue CONNECT requests to establish tunnels through the authenticated proxy without providing credentials, enabling arbitrary TCP traffic relay and access to restricted destinations.

Severity

6.9 (Medium)


                        
                          CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

7.2 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

CWE

CWE-288 - Authentication Bypass Using an Alternate Path or Channel

Assigner

VulnCheck mitre root

References

5 references

URL	Tags
https://github.com/geo-chen/oss/blob/main/goproxy.md	third-party-advisoryexploit
https://github.com/snail007/goproxy/blob/v15.3/ut…	technical-description
https://github.com/snail007/goproxy/blob/v15.3/se…	technical-description
https://github.com/snail007/goproxy	product
https://www.vulncheck.com/advisories/goproxy-thro…	third-party-advisory

Impacted products

1 product

Vendor	Product	Version	CPE status
snail007	goproxy	Affected: 0 , ≤ 15.3 (custom) cpe:2.3:a:goproxy_project:goproxy::::::::

Date Public

2026-07-29 00:00

Credits

George Chen

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "packageURL": "pkg:golang/github.com/snail007/goproxy",
          "product": "goproxy",
          "repo": "https://github.com/snail007/goproxy",
          "vendor": "snail007",
          "versions": [
            {
              "lessThanOrEqual": "15.3",
              "status": "affected",
              "version": "0",
              "versionType": "custom"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:a:goproxy_project:goproxy:*:*:*:*:*:*:*:*",
                  "versionEndIncluding": "15.3",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "reporter",
          "value": "George Chen"
        }
      ],
      "datePublic": "2026-07-29T00:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "goproxy through 15.3 fails to apply HTTP proxy basic authentication to CONNECT tunnel requests, allowing unauthenticated clients to bypass credential requirements. Attackers can issue CONNECT requests to establish tunnels through the authenticated proxy without providing credentials, enabling arbitrary TCP traffic relay and access to restricted destinations."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 6.9,
            "baseSeverity": "MEDIUM",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "LOW",
            "subIntegrityImpact": "LOW",
            "userInteraction": "NONE",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "NONE"
          },
          "format": "CVSS"
        },
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 7.2,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "LOW",
            "integrityImpact": "LOW",
            "privilegesRequired": "NONE",
            "scope": "CHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N",
            "version": "3.1"
          },
          "format": "CVSS"
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-288",
              "description": "Authentication Bypass Using an Alternate Path or Channel",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-14T21:45:43.908Z",
        "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
        "shortName": "VulnCheck"
      },
      "references": [
        {
          "name": "Researcher write-up",
          "tags": [
            "third-party-advisory",
            "exploit"
          ],
          "url": "https://github.com/geo-chen/oss/blob/main/goproxy.md"
        },
        {
          "name": "utils/structs.go at v15.3",
          "tags": [
            "technical-description"
          ],
          "url": "https://github.com/snail007/goproxy/blob/v15.3/utils/structs.go"
        },
        {
          "name": "services/http.go at v15.3",
          "tags": [
            "technical-description"
          ],
          "url": "https://github.com/snail007/goproxy/blob/v15.3/services/http.go"
        },
        {
          "tags": [
            "product"
          ],
          "url": "https://github.com/snail007/goproxy"
        },
        {
          "name": "VulnCheck Advisory: goproxy through 15.3 Authentication Bypass via CONNECT",
          "tags": [
            "third-party-advisory"
          ],
          "url": "https://www.vulncheck.com/advisories/goproxy-through-15.3-authentication-bypass-via-connect"
        }
      ],
      "title": "goproxy through 15.3 Authentication Bypass via CONNECT",
      "x_generator": {
        "engine": "vulncheck-endgame"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
    "assignerShortName": "VulnCheck",
    "cveId": "CVE-2026-91143",
    "datePublished": "2026-09-14T21:45:43.908Z",
    "dateReserved": "2026-09-14T20:35:39.074Z",
    "dateUpdated": "2026-09-14T21:45:43.908Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-91143\",\"sourceIdentifier\":\"disclosure@vulncheck.com\",\"published\":\"2026-09-14T22:16:58.880\",\"lastModified\":\"2026-09-14T22:16:58.880\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"goproxy through 15.3 fails to apply HTTP proxy basic authentication to CONNECT tunnel requests, allowing unauthenticated clients to bypass credential requirements. Attackers can issue CONNECT requests to establish tunnels through the authenticated proxy without providing credentials, enabling arbitrary TCP traffic relay and access to restricted destinations.\"}],\"affected\":[{\"source\":\"disclosure@vulncheck.com\",\"affectedData\":[{\"vendor\":\"snail007\",\"product\":\"goproxy\",\"defaultStatus\":\"unaffected\",\"repo\":\"https://github.com/snail007/goproxy\",\"packageURL\":\"pkg:golang/github.com/snail007/goproxy\",\"versions\":[{\"version\":\"0\",\"lessThanOrEqual\":\"15.3\",\"versionType\":\"custom\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV40\":[{\"source\":\"disclosure@vulncheck.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"4.0\",\"vectorString\":\"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X\",\"baseScore\":6.9,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"attackRequirements\":\"NONE\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"vulnConfidentialityImpact\":\"NONE\",\"vulnIntegrityImpact\":\"NONE\",\"vulnAvailabilityImpact\":\"NONE\",\"subConfidentialityImpact\":\"LOW\",\"subIntegrityImpact\":\"LOW\",\"subAvailabilityImpact\":\"NONE\",\"exploitMaturity\":\"NOT_DEFINED\",\"confidentialityRequirement\":\"NOT_DEFINED\",\"integrityRequirement\":\"NOT_DEFINED\",\"availabilityRequirement\":\"NOT_DEFINED\",\"modifiedAttackVector\":\"NOT_DEFINED\",\"modifiedAttackComplexity\":\"NOT_DEFINED\",\"modifiedAttackRequirements\":\"NOT_DEFINED\",\"modifiedPrivilegesRequired\":\"NOT_DEFINED\",\"modifiedUserInteraction\":\"NOT_DEFINED\",\"modifiedVulnConfidentialityImpact\":\"NOT_DEFINED\",\"modifiedVulnIntegrityImpact\":\"NOT_DEFINED\",\"modifiedVulnAvailabilityImpact\":\"NOT_DEFINED\",\"modifiedSubConfidentialityImpact\":\"NOT_DEFINED\",\"modifiedSubIntegrityImpact\":\"NOT_DEFINED\",\"modifiedSubAvailabilityImpact\":\"NOT_DEFINED\",\"Safety\":\"NOT_DEFINED\",\"Automatable\":\"NOT_DEFINED\",\"Recovery\":\"NOT_DEFINED\",\"valueDensity\":\"NOT_DEFINED\",\"vulnerabilityResponseEffort\":\"NOT_DEFINED\",\"providerUrgency\":\"NOT_DEFINED\"}}],\"cvssMetricV31\":[{\"source\":\"disclosure@vulncheck.com\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N\",\"baseScore\":7.2,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"CHANGED\",\"confidentialityImpact\":\"LOW\",\"integrityImpact\":\"LOW\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":3.9,\"impactScore\":2.7}]},\"weaknesses\":[{\"source\":\"disclosure@vulncheck.com\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-288\"}]}],\"references\":[{\"url\":\"https://github.com/geo-chen/oss/blob/main/goproxy.md\",\"source\":\"disclosure@vulncheck.com\"},{\"url\":\"https://github.com/snail007/goproxy\",\"source\":\"disclosure@vulncheck.com\"},{\"url\":\"https://github.com/snail007/goproxy/blob/v15.3/services/http.go\",\"source\":\"disclosure@vulncheck.com\"},{\"url\":\"https://github.com/snail007/goproxy/blob/v15.3/utils/structs.go\",\"source\":\"disclosure@vulncheck.com\"},{\"url\":\"https://www.vulncheck.com/advisories/goproxy-through-15.3-authentication-bypass-via-connect\",\"source\":\"disclosure@vulncheck.com\"}]}}"
  }
}

FKIE_CVE-2026-91143

Vulnerability from fkie_nvd - Published: 2026-09-14 22:16 - Updated: 2026-09-14 22:16

Severity

7.2 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

Summary

References

	URL	Tags
	disclosure@vulncheck.com	https://github.com/geo-chen/oss/blob/main/goproxy.md
	disclosure@vulncheck.com	https://github.com/snail007/goproxy
	disclosure@vulncheck.com	https://github.com/snail007/goproxy/blob/v15.3/services/http.go
	disclosure@vulncheck.com	https://github.com/snail007/goproxy/blob/v15.3/utils/structs.go
	disclosure@vulncheck.com	https://www.vulncheck.com/advisories/goproxy-through-15.3-authentication-bypass-via-connect

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "packageURL": "pkg:golang/github.com/snail007/goproxy",
          "product": "goproxy",
          "repo": "https://github.com/snail007/goproxy",
          "vendor": "snail007",
          "versions": [
            {
              "lessThanOrEqual": "15.3",
              "status": "affected",
              "version": "0",
              "versionType": "custom"
            }
          ]
        }
      ],
      "source": "disclosure@vulncheck.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "goproxy through 15.3 fails to apply HTTP proxy basic authentication to CONNECT tunnel requests, allowing unauthenticated clients to bypass credential requirements. Attackers can issue CONNECT requests to establish tunnels through the authenticated proxy without providing credentials, enabling arbitrary TCP traffic relay and access to restricted destinations."
    }
  ],
  "id": "CVE-2026-91143",
  "lastModified": "2026-09-14T22:16:58.880",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 7.2,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "LOW",
          "integrityImpact": "LOW",
          "privilegesRequired": "NONE",
          "scope": "CHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 2.7,
        "source": "disclosure@vulncheck.com",
        "type": "Primary"
      }
    ],
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "attackVector": "NETWORK",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 6.9,
          "baseSeverity": "MEDIUM",
          "confidentialityRequirement": "NOT_DEFINED",
          "exploitMaturity": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "privilegesRequired": "NONE",
          "providerUrgency": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "LOW",
          "subIntegrityImpact": "LOW",
          "userInteraction": "NONE",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
          "version": "4.0",
          "vulnAvailabilityImpact": "NONE",
          "vulnConfidentialityImpact": "NONE",
          "vulnIntegrityImpact": "NONE",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "disclosure@vulncheck.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-09-14T22:16:58.880",
  "references": [
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://github.com/geo-chen/oss/blob/main/goproxy.md"
    },
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://github.com/snail007/goproxy"
    },
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://github.com/snail007/goproxy/blob/v15.3/services/http.go"
    },
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://github.com/snail007/goproxy/blob/v15.3/utils/structs.go"
    },
    {
      "source": "disclosure@vulncheck.com",
      "url": "https://www.vulncheck.com/advisories/goproxy-through-15.3-authentication-bypass-via-connect"
    }
  ],
  "sourceIdentifier": "disclosure@vulncheck.com",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-288"
        }
      ],
      "source": "disclosure@vulncheck.com",
      "type": "Primary"
    }
  ]
}

GHSA-PVFX-F5GX-WJ35

Vulnerability from github – Published: 2026-09-15 00:31 – Updated: 2026-09-15 00:31

Details

Severity

7.2 (High)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

6.9 (Medium)


                  
                    CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-91143"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-288"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-14T22:16:58Z",
    "severity": "MODERATE"
  },
  "details": "goproxy through 15.3 fails to apply HTTP proxy basic authentication to CONNECT tunnel requests, allowing unauthenticated clients to bypass credential requirements. Attackers can issue CONNECT requests to establish tunnels through the authenticated proxy without providing credentials, enabling arbitrary TCP traffic relay and access to restricted destinations.",
  "id": "GHSA-pvfx-f5gx-wj35",
  "modified": "2026-09-15T00:31:13Z",
  "published": "2026-09-15T00:31:13Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-91143"
    },
    {
      "type": "WEB",
      "url": "https://github.com/geo-chen/oss/blob/main/goproxy.md"
    },
    {
      "type": "WEB",
      "url": "https://github.com/snail007/goproxy"
    },
    {
      "type": "WEB",
      "url": "https://github.com/snail007/goproxy/blob/v15.3/services/http.go"
    },
    {
      "type": "WEB",
      "url": "https://github.com/snail007/goproxy/blob/v15.3/utils/structs.go"
    },
    {
      "type": "WEB",
      "url": "https://www.vulncheck.com/advisories/goproxy-through-15.3-authentication-bypass-via-connect"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}

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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

Action not permitted

CVE-2026-91143 (GCVE-0-2026-91143)

FKIE_CVE-2026-91143

GHSA-PVFX-F5GX-WJ35

Tags

Sightings

Nomenclature