CVE-2026-87861

Full vulnerability record from the local CVENow database.

Description

When using ambient user credentials, an HTTP request directed to one origin may be dispatched over a connection previously authenticated via Negotiate for a different origin, leaving the request's intended credentials unused.

Severity

CRITICAL

CVSS score

9.1 (v3.1)

Vulnerability status

Awaiting Analysis

Source identifier

2499f714-1537-4658-8207-48ae4bb9eae9

Published

2026-10-20 21:17:20.167000

Last modified

2026-10-30 12:16:45.617000

View original CVE JSON

{
  "id": "CVE-2026-87861",
  "sourceIdentifier": "2499f714-1537-4658-8207-48ae4bb9eae9",
  "published": "2026-10-20T21:17:20.167",
  "lastModified": "2026-10-30T12:16:45.617",
  "vulnStatus": "Awaiting Analysis",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "When using ambient user credentials, an HTTP request directed to one origin\nmay be dispatched over a connection previously authenticated via Negotiate for\na different origin, leaving the request's intended credentials unused."
    }
  ],
  "affected": [
    {
      "source": "2499f714-1537-4658-8207-48ae4bb9eae9",
      "affectedData": [
        {
          "vendor": "curl",
          "product": "curl",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "8.22.0",
              "lessThanOrEqual": "8.22.0",
              "versionType": "semver",
              "status": "affected"
            },
            {
              "version": "8.21.0",
              "lessThanOrEqual": "8.21.0",
              "versionType": "semver",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
          "baseScore": 9.1,
          "baseSeverity": "CRITICAL",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "availabilityImpact": "NONE"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.2
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-10-30T11:54:54.295912Z",
          "id": "CVE-2026-87861",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-201"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://curl.se/docs/CVE-2026-87861.html",
      "source": "2499f714-1537-4658-8207-48ae4bb9eae9"
    },
    {
      "url": "https://curl.se/docs/CVE-2026-87861.json",
      "source": "2499f714-1537-4658-8207-48ae4bb9eae9"
    },
    {
      "url": "https://hackerone.com/reports/3972094",
      "source": "2499f714-1537-4658-8207-48ae4bb9eae9"
    },
    {
      "url": "https://hackerone.com/reports/3972094",
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"
    }
  ]
}