CVE-2026-86413

Full vulnerability record from the local CVENow database.

Description

When using an *ambient user* in a first transfer doing Negotiate authentication and asked to follow redirects, curl could pass on its credential details to an unrelated second origin when asked to redirect there.

Severity

CRITICAL

CVSS score

9.1 (v3.1)

Vulnerability status

Awaiting Analysis

Source identifier

2499f714-1537-4658-8207-48ae4bb9eae9

Published

2026-10-20 20:17:25.787000

Last modified

2026-10-30 12:16:45.040000

View original CVE JSON

{
  "id": "CVE-2026-86413",
  "sourceIdentifier": "2499f714-1537-4658-8207-48ae4bb9eae9",
  "published": "2026-10-20T20:17:25.787",
  "lastModified": "2026-10-30T12:16:45.040",
  "vulnStatus": "Awaiting Analysis",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "When using an *ambient user* in a first transfer doing Negotiate\nauthentication and asked to follow redirects, curl could pass on its\ncredential details to an unrelated second origin when asked to redirect there."
    }
  ],
  "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": "2026-10-30T11:43:03.805545Z",
          "id": "CVE-2026-86413",
          "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-2026-86413.html",
      "source": "2499f714-1537-4658-8207-48ae4bb9eae9"
    },
    {
      "url": "https://curl.se/docs/CVE-2026-86413.json",
      "source": "2499f714-1537-4658-8207-48ae4bb9eae9"
    },
    {
      "url": "https://hackerone.com/reports/3993549",
      "source": "2499f714-1537-4658-8207-48ae4bb9eae9"
    },
    {
      "url": "https://hackerone.com/reports/3993549",
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"
    }
  ]
}